From a3ac0feddf585832286b8beb1d59ee781b610c15 Mon Sep 17 00:00:00 2001
From: Timothy Cardoza <tcardoza@cardoza.construction>
Date: Fri, 20 Mar 2026 15:11:32 -0500
Subject: [PATCH] Added prevailing wage calculator and custom math modifiers

---
 src/components/ExportTableModal.tsx           |  19 +-
 src/components/ItemRow.tsx                    | 115 +++--
 src/components/ModifierRow.tsx                | 240 +++++++++-
 src/components/PrintEstimate.tsx              |  35 +-
 src/components/ScopeCard.tsx                  |  47 +-
 src/components/SubScopeCard.tsx               |  22 +-
 .../useEstimateCalculations.ts                |  41 +-
 src/store/appStore.ts                         |  16 +-
 src/types.ts                                  |   8 +-
 src/utils/modifier-registry.ts                |  75 +++-
 src/utils/pricing.ts                          | 412 ++++++++++++++++++
 src/views/TemplateCreator.tsx                 |  14 +-
 12 files changed, 881 insertions(+), 163 deletions(-)
 create mode 100644 src/utils/pricing.ts

diff --git a/src/components/ExportTableModal.tsx b/src/components/ExportTableModal.tsx
index 900f102..e89003a 100644
--- a/src/components/ExportTableModal.tsx
+++ b/src/components/ExportTableModal.tsx
@@ -3,6 +3,7 @@ import { createSignal, Show, For, onMount } from 'solid-js';
 import { Portal } from 'solid-js/web';
 import { X, Table, Copy, Download, CheckCircle2 } from 'lucide-solid';
 import { appStore } from '../store/appStore';
+import { getEffectiveItemPricing } from '../utils/pricing';
 
 interface ExportTableModalProps {
     show: boolean;
@@ -93,22 +94,18 @@ const ExportTableModal: Component<ExportTableModalProps> = (props) => {
         filteredItems.forEach(item => {
             const scope = scopes().find(s => s.id === item.scopeId);
             const subScope = subScopes().find(ss => ss.id === item.subScopeId);
-
-            const base = item.quantity * item.unitPrice;
-            const markupAmt = item.markupType === 'percent' ? base * (item.markup / 100) : item.markup;
-            const contingencyAmt = item.contingencyType === 'percent' ? base * (item.contingency / 100) : item.contingency;
-            const total = base + markupAmt + contingencyAmt;
+            const pricing = getEffectiveItemPricing(item, subScope?.modifiers || []);
 
             dataRows.push({
                 scope: scope?.name || 'Unassigned',
                 subscope: subScope?.name || 'Scope Level',
                 description: item.description,
-                quantity: item.quantity,
-                unitPrice: item.unitPrice,
-                subtotal: base,
-                markup: markupAmt,
-                contingency: contingencyAmt,
-                total: total
+                quantity: pricing.effectiveQuantity,
+                unitPrice: pricing.effectiveUnitPrice,
+                subtotal: pricing.effectiveSubtotal,
+                markup: pricing.markupAmount,
+                contingency: pricing.contingencyAmount,
+                total: pricing.total
             });
         });
 
diff --git a/src/components/ItemRow.tsx b/src/components/ItemRow.tsx
index 22eaadd..2fc6929 100644
--- a/src/components/ItemRow.tsx
+++ b/src/components/ItemRow.tsx
@@ -3,8 +3,9 @@ import { createMemo, createEffect, createSignal, Show, For, onCleanup } from 'so
 import { Portal } from 'solid-js/web';
 import { GripVertical, Trash2, Copy } from 'lucide-solid';
 import NumericInput from './ui/NumericInput';
-import type { EstimateItem, StandardPrice } from '../types';
+import type { EstimateItem, Modifier, StandardPrice } from '../types';
 import { pb, COLLECTIONS } from '../utils/db';
+import { getEffectiveItemPricing } from '../utils/pricing';
 
 interface ItemRowProps {
     item: EstimateItem;
@@ -18,23 +19,15 @@ interface ItemRowProps {
     onDuplicateItem: (id: string) => void;
     hideColumns?: boolean;
     activeSupplier?: string;
+    subScopeModifiers?: Modifier[];
 }
 
 const ItemRow: Component<ItemRowProps> = (props) => {
     let descriptionRef: HTMLTextAreaElement | undefined;
 
-    const baseTotal = createMemo(() => props.item.quantity * props.item.unitPrice);
-
-    const total = createMemo(() => {
-        const base = baseTotal();
-        const markup = props.item.markupType === 'percent'
-            ? base * (props.item.markup / 100)
-            : props.item.markup;
-        const contingency = props.item.contingencyType === 'percent'
-            ? base * (props.item.contingency / 100)
-            : props.item.contingency;
-        return base + markup + contingency;
-    });
+    const pricing = createMemo(() => getEffectiveItemPricing(props.item, props.subScopeModifiers || []));
+    const subtotal = createMemo(() => pricing().effectiveSubtotal);
+    const total = createMemo(() => pricing().total);
 
     const [isSearchingPrice, setIsSearchingPrice] = createSignal(false);
     const [searchResults, setSearchResults] = createSignal<StandardPrice[]>([]);
@@ -272,7 +265,7 @@ const ItemRow: Component<ItemRowProps> = (props) => {
                         value={props.item.quantity}
                         onUpdate={(val) => props.onUpdate(props.item.id, { quantity: val })}
                         onDragStart={(e) => {
-                            const val = props.item.quantity;
+                            const val = pricing().effectiveQuantity;
                             const data = { type: 'item-field', itemId: props.item.id, fieldName: 'qty', value: val, label: `${props.item.description || 'Unnamed Item'}: Qty` };
                             e.dataTransfer!.setData('application/json', JSON.stringify(data));
                             e.dataTransfer!.setData('text/plain', String(val));
@@ -284,35 +277,49 @@ const ItemRow: Component<ItemRowProps> = (props) => {
                         class="w-full bg-muted/30 border border-border/60 rounded-xl px-2 py-1.5 text-xs text-right focus:bg-background focus:ring-2 focus:ring-primary/20 focus:border-primary outline-none disabled:opacity-50 cursor-text font-bold text-foreground/80 transition-all"
                         placeholder="Qty"
                     />
+                    <Show when={pricing().hasDirectQuantityAdjustment}>
+                        <div class="mt-1 text-right text-[9px] font-black uppercase tracking-[0.15em] text-primary">
+                            Adj {formatNumber(pricing().effectiveQuantity)}
+                        </div>
+                    </Show>
                 </div>
 
                 {/* Price — w-24 */}
                 <div class="w-24 shrink-0 relative" ref={anchorRef}>
-                    <span class="absolute left-2.5 top-1/2 -translate-y-1/2 text-muted-foreground/50 text-[10px] pointer-events-none">$</span>
-                    <NumericInput
-                        inputRef={(el: any) => desktopInputRef = el}
-                        dataFieldName="price"
-                        step="0.1"
-                        value={props.item.unitPrice}
-                        onUpdate={(val) => props.onUpdate(props.item.id, { unitPrice: val })}
-                        onDragStart={(e) => {
-                            const val = props.item.unitPrice;
-                            const data = { type: 'item-field', itemId: props.item.id, fieldName: 'price', value: val, label: `${props.item.description || 'Unnamed Item'}: Price` };
-                            e.dataTransfer!.setData('application/json', JSON.stringify(data));
-                            e.dataTransfer!.setData('text/plain', String(val));
-                            e.dataTransfer!.effectAllowed = 'copy';
-                            e.stopPropagation();
-                        }}
-                        draggable="true"
-                        disabled={props.anySelected}
-                        class="w-full bg-muted/30 border border-border/60 rounded-xl pl-5 pr-2 py-1.5 text-xs text-right focus:bg-background focus:ring-2 focus:ring-primary/20 focus:border-primary outline-none disabled:opacity-50 cursor-text font-bold text-foreground/80 transition-all"
-                        placeholder="Price"
-                        allowTextSearch={true}
-                        onTextSearch={handlePriceSearch}
-                        onKeyDown={handlePriceKeyDown}
-                        onTextSearchExit={() => setIsSearchingPrice(false)}
-                        onBlur={() => setTimeout(() => setIsSearchingPrice(false), 150)}
-                    />
+                    <div class="space-y-1">
+                        <div class="relative">
+                            <span class="absolute left-2.5 top-1/2 -translate-y-1/2 text-muted-foreground/50 text-[10px] pointer-events-none">$</span>
+                            <NumericInput
+                                inputRef={(el: any) => desktopInputRef = el}
+                                dataFieldName="price"
+                                step="0.1"
+                                value={props.item.unitPrice}
+                                onUpdate={(val) => props.onUpdate(props.item.id, { unitPrice: val })}
+                                onDragStart={(e) => {
+                                    const val = pricing().effectiveUnitPrice;
+                                    const data = { type: 'item-field', itemId: props.item.id, fieldName: 'price', value: val, label: `${props.item.description || 'Unnamed Item'}: Price` };
+                                    e.dataTransfer!.setData('application/json', JSON.stringify(data));
+                                    e.dataTransfer!.setData('text/plain', String(val));
+                                    e.dataTransfer!.effectAllowed = 'copy';
+                                    e.stopPropagation();
+                                }}
+                                draggable="true"
+                                disabled={props.anySelected}
+                                class="w-full bg-muted/30 border border-border/60 rounded-xl pl-5 pr-2 py-1.5 text-xs text-right focus:bg-background focus:ring-2 focus:ring-primary/20 focus:border-primary outline-none disabled:opacity-50 cursor-text font-bold text-foreground/80 transition-all"
+                                placeholder="Price"
+                                allowTextSearch={true}
+                                onTextSearch={handlePriceSearch}
+                                onKeyDown={handlePriceKeyDown}
+                                onTextSearchExit={() => setIsSearchingPrice(false)}
+                                onBlur={() => setTimeout(() => setIsSearchingPrice(false), 150)}
+                            />
+                        </div>
+                        <Show when={pricing().hasDirectUnitPriceAdjustment}>
+                            <div class="text-right text-[9px] font-black uppercase tracking-[0.15em] text-primary">
+                                Adj ${formatNumber(pricing().effectiveUnitPrice)}
+                            </div>
+                        </Show>
+                    </div>
                     <PriceDropdown />
                 </div>
 
@@ -320,7 +327,7 @@ const ItemRow: Component<ItemRowProps> = (props) => {
                 <div
                     draggable="true"
                     onDragStart={(e) => {
-                        const val = baseTotal();
+                        const val = subtotal();
                         const data = { type: 'item-field', itemId: props.item.id, fieldName: 'subtotal', value: val, label: `${props.item.description || 'Unnamed Item'}: Subtotal` };
                         e.dataTransfer!.setData('application/json', JSON.stringify(data));
                         e.dataTransfer!.setData('text/plain', String(val));
@@ -329,7 +336,15 @@ const ItemRow: Component<ItemRowProps> = (props) => {
                     }}
                     class="w-24 shrink-0 text-right text-muted-foreground/60 text-[11px] font-bold uppercase tracking-tighter cursor-grab hover:text-primary transition-colors"
                 >
-                    ${formatNumber(baseTotal())}
+                    <div>${formatNumber(pricing().baseSubtotal)}</div>
+                    <Show when={pricing().hasAdjustedSubtotal}>
+                        <div class="mt-1 text-[9px] font-black uppercase tracking-[0.15em] text-primary">
+                            Adjusted
+                        </div>
+                        <div class="text-[10px] font-black text-primary">
+                            ${formatNumber(subtotal())}
+                        </div>
+                    </Show>
                 </div>
 
                 {/* Markup — w-32 (conditional) */}
@@ -465,6 +480,11 @@ const ItemRow: Component<ItemRowProps> = (props) => {
                     <div class="w-20">
                         <div class="text-[9px] font-bold text-muted-foreground/60 uppercase mb-1 ml-1">Qty</div>
                         <NumericInput value={props.item.quantity} onUpdate={(val) => props.onUpdate(props.item.id, { quantity: val })} disabled={props.anySelected} class="w-full bg-muted/30 border border-border/60 rounded-xl px-2 py-1.5 text-xs text-right focus:bg-background focus:ring-2 focus:ring-primary/20 focus:border-primary outline-none disabled:opacity-50 font-bold text-foreground/80 transition-all" placeholder="Qty" />
+                        <Show when={pricing().hasDirectQuantityAdjustment}>
+                            <div class="mt-1 text-right text-[9px] font-black uppercase tracking-[0.15em] text-primary">
+                                Adj {formatNumber(pricing().effectiveQuantity)}
+                            </div>
+                        </Show>
                     </div>
                     <div class="w-24">
                         <div class="text-[9px] font-bold text-muted-foreground/60 uppercase mb-1 ml-1">Price</div>
@@ -473,6 +493,11 @@ const ItemRow: Component<ItemRowProps> = (props) => {
                             <NumericInput inputRef={(el: any) => mobileInputRef = el} step="0.1" value={props.item.unitPrice} onUpdate={(val) => props.onUpdate(props.item.id, { unitPrice: val })} disabled={props.anySelected} class="w-full bg-muted/30 border border-border/60 rounded-xl pl-5 pr-2 py-1.5 text-xs text-right focus:bg-background focus:ring-2 focus:ring-primary/20 focus:border-primary outline-none disabled:opacity-50 font-bold text-foreground/80 transition-all" placeholder="Price" allowTextSearch={true} onTextSearch={handlePriceSearch} onKeyDown={handlePriceKeyDown} onTextSearchExit={() => setIsSearchingPrice(false)} onBlur={() => setTimeout(() => setIsSearchingPrice(false), 150)} />
                             <PriceDropdown />
                         </div>
+                        <Show when={pricing().hasDirectUnitPriceAdjustment}>
+                            <div class="mt-1 text-right text-[9px] font-black uppercase tracking-[0.15em] text-primary">
+                                Adj ${formatNumber(pricing().effectiveUnitPrice)}
+                            </div>
+                        </Show>
                     </div>
                     <Show when={props.isSidebarCollapsed() || !props.hideColumns}>
                         <div class="w-32">
@@ -495,6 +520,14 @@ const ItemRow: Component<ItemRowProps> = (props) => {
                         <div class={`font-black text-sm text-right ${props.isSelected ? 'text-primary' : 'text-foreground'}`}>${formatNumber(total())}</div>
                     </div>
                 </div>
+                <Show when={pricing().hasDirectSubtotalAdjustment || pricing().hasAdjustedSubtotal}>
+                    <div class="pl-7 text-right text-[10px] font-black uppercase tracking-[0.15em] text-primary/70">
+                        Adjusted
+                    </div>
+                    <div class="pl-7 text-right text-sm font-black text-primary">
+                        ${formatNumber(pricing().effectiveSubtotal)}
+                    </div>
+                </Show>
             </div>
         </div>
     );
diff --git a/src/components/ModifierRow.tsx b/src/components/ModifierRow.tsx
index ba1ce79..21ed9a2 100644
--- a/src/components/ModifierRow.tsx
+++ b/src/components/ModifierRow.tsx
@@ -1,9 +1,17 @@
 import type { Component } from 'solid-js';
-import { Show } from 'solid-js';
+import { Show, createMemo } from 'solid-js';
 import { Trash2, Calculator, EyeOff } from 'lucide-solid';
 import NumericInput from './ui/NumericInput';
 import type { Modifier } from '../types';
 import { ModifierRegistry } from '../utils/modifier-registry';
+import {
+    CUSTOM_CALC_DEFAULT_EXPRESSION,
+    getComputedModifierStatus,
+    isComputedFieldModifier,
+    isCustomCalculationModifier,
+    isPrevailingWageModifier,
+    TARGET_FIELD_LABELS
+} from '../utils/pricing';
 
 interface ModifierRowProps {
     modifier: Modifier;
@@ -13,16 +21,233 @@ interface ModifierRowProps {
 }
 
 const ModifierRow: Component<ModifierRowProps> = (props) => {
-    const module = () => ModifierRegistry.getModule(props.modifier.moduleId);
+    const module = () => ModifierRegistry.getModule(props.modifier.moduleId, props.modifier);
+    const computedStatus = createMemo(() => getComputedModifierStatus(props.modifier));
+    const isPrevailing = () => isPrevailingWageModifier(props.modifier);
+    const isCustom = () => isCustomCalculationModifier(props.modifier);
+    const isComputed = () => isComputedFieldModifier(props.modifier);
 
     const formatNumber = (num: number) => {
         return num.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 });
     };
 
+    if (isPrevailing()) {
+        return (
+            <div class="rounded-2xl border border-border/60 bg-background/70 p-4 space-y-3">
+                <div class="flex items-start justify-between gap-4">
+                    <div class="min-w-0 flex-1 space-y-3">
+                        <div class="flex items-center gap-3">
+                            <input
+                                type="text"
+                                title={module().description}
+                                value={props.modifier.name}
+                                onInput={(e) => props.onUpdate(props.modifier.id, { name: e.currentTarget.value })}
+                                class="bg-transparent border-none outline-none text-sm font-semibold text-foreground focus:ring-0 py-0.5 w-48"
+                                placeholder="Modifier Name"
+                            />
+                            <span class="rounded-full bg-primary/10 px-2 py-0.5 text-[9px] font-black uppercase tracking-[0.2em] text-primary">
+                                Unit Price
+                            </span>
+                        </div>
+
+                        <div class="grid gap-3 md:grid-cols-[120px_120px_auto]">
+                            <div>
+                                <div class="mb-1 text-[9px] font-black uppercase tracking-[0.2em] text-muted-foreground">Base Rate</div>
+                                <NumericInput
+                                    value={computedStatus().parameters.baseRate ?? 0}
+                                    onUpdate={(val) => props.onUpdate(props.modifier.id, {
+                                        targetField: 'unitPrice',
+                                        parameters: {
+                                            ...computedStatus().parameters,
+                                            baseRate: val
+                                        }
+                                    })}
+                                    class="w-full rounded-xl border border-border/60 bg-muted/30 px-3 py-2 text-right text-xs font-bold text-foreground outline-none transition-all focus:border-primary focus:bg-background"
+                                />
+                            </div>
+                            <div>
+                                <div class="mb-1 text-[9px] font-black uppercase tracking-[0.2em] text-muted-foreground">Prevailing</div>
+                                <NumericInput
+                                    value={computedStatus().parameters.prevailingRate ?? 0}
+                                    onUpdate={(val) => props.onUpdate(props.modifier.id, {
+                                        targetField: 'unitPrice',
+                                        parameters: {
+                                            ...computedStatus().parameters,
+                                            prevailingRate: val
+                                        }
+                                    })}
+                                    class="w-full rounded-xl border border-border/60 bg-muted/30 px-3 py-2 text-right text-xs font-bold text-foreground outline-none transition-all focus:border-primary focus:bg-background"
+                                />
+                            </div>
+                            <div class="flex items-end">
+                                <div class="rounded-xl border border-border/60 bg-muted/20 px-3 py-2 text-[10px] font-black uppercase tracking-[0.15em] text-muted-foreground">
+                                    <Show when={!computedStatus().error && computedStatus().multiplier !== undefined} fallback={'Formula: price * multiplier'}>
+                                        Multiplier {computedStatus().multiplier?.toFixed(4)}x
+                                    </Show>
+                                </div>
+                            </div>
+                        </div>
+                        <Show when={computedStatus().error}>
+                            <div class="min-h-[1rem] text-[10px] font-bold uppercase tracking-widest text-destructive">
+                                {computedStatus().error}
+                            </div>
+                        </Show>
+                    </div>
+
+                    <div class="flex items-center gap-2">
+                        <button
+                            onClick={() => props.onUpdate(props.modifier.id, { includeInTotal: !props.modifier.includeInTotal })}
+                            class={`p-1.5 rounded-lg transition-all ${props.modifier.includeInTotal ? 'text-primary' : 'text-muted-foreground/30'}`}
+                            title={props.modifier.includeInTotal ? 'Included' : 'Excluded'}
+                        >
+                            <Show when={props.modifier.includeInTotal} fallback={<EyeOff class="w-3.5 h-3.5" />}>
+                                <Calculator class="w-3.5 h-3.5" />
+                            </Show>
+                        </button>
+                        <button
+                            onClick={() => props.onDelete(props.modifier.id)}
+                            class="p-1.5 text-muted-foreground/40 hover:text-destructive hover:bg-destructive/10 rounded-lg transition-all"
+                        >
+                            <Trash2 class="w-3.5 h-3.5" />
+                        </button>
+                    </div>
+                </div>
+            </div>
+        );
+    }
+
+    if (isCustom()) {
+        return (
+            <div class="rounded-2xl border border-border/60 bg-background/70 p-4 space-y-3">
+                <div class="flex items-start justify-between gap-4">
+                    <div class="min-w-0 flex-1 space-y-3">
+                        <div class="flex items-center gap-3">
+                            <input
+                                type="text"
+                                title={module().description}
+                                value={props.modifier.name}
+                                onInput={(e) => props.onUpdate(props.modifier.id, { name: e.currentTarget.value })}
+                                class="bg-transparent border-none outline-none text-sm font-semibold text-foreground focus:ring-0 py-0.5 w-48"
+                                placeholder="Modifier Name"
+                            />
+                            <select
+                                value={computedStatus().targetField}
+                                onChange={(e) => props.onUpdate(props.modifier.id, { targetField: e.currentTarget.value as Modifier['targetField'] })}
+                                class="rounded-lg border border-border bg-background px-2 py-1 text-[10px] font-black uppercase tracking-wider text-muted-foreground outline-none focus:border-primary"
+                            >
+                                <option value="unitPrice">{TARGET_FIELD_LABELS.unitPrice}</option>
+                                <option value="quantity">{TARGET_FIELD_LABELS.quantity}</option>
+                                <option value="subtotal">{TARGET_FIELD_LABELS.subtotal}</option>
+                            </select>
+                        </div>
+
+                        <div>
+                            <div class="mb-1 flex items-center justify-between text-[9px] font-black uppercase tracking-[0.2em] text-muted-foreground">
+                                <span>Math</span>
+                                <span class="text-primary">Inputs: price, quantity, subtotal</span>
+                            </div>
+                            <input
+                                type="text"
+                                value={computedStatus().expression}
+                                onInput={(e) => props.onUpdate(props.modifier.id, { expression: e.currentTarget.value })}
+                                class="w-full rounded-xl border border-border/60 bg-muted/30 px-3 py-2 text-xs font-mono text-foreground outline-none transition-all focus:border-primary focus:bg-background"
+                                placeholder={CUSTOM_CALC_DEFAULT_EXPRESSION}
+                            />
+                        </div>
+
+                        <div class="flex items-center justify-between gap-4">
+                            <div class="min-h-[1rem] text-[10px] font-bold uppercase tracking-widest">
+                                <Show
+                                    when={!computedStatus().error}
+                                    fallback={<span class="text-destructive">{computedStatus().error}</span>}
+                                >
+                                    <span class="text-primary/70">
+                                        Output updates {TARGET_FIELD_LABELS[computedStatus().targetField].toLowerCase()}
+                                    </span>
+                                </Show>
+                            </div>
+                            <div class="text-right text-[10px] font-black uppercase tracking-[0.2em] text-muted-foreground">
+                                Base inputs stay editable
+                            </div>
+                        </div>
+                    </div>
+
+                    <div class="flex items-center gap-2">
+                        <button
+                            onClick={() => props.onUpdate(props.modifier.id, { includeInTotal: !props.modifier.includeInTotal })}
+                            class={`p-1.5 rounded-lg transition-all ${props.modifier.includeInTotal ? 'text-primary' : 'text-muted-foreground/30'}`}
+                            title={props.modifier.includeInTotal ? 'Included' : 'Excluded'}
+                        >
+                            <Show when={props.modifier.includeInTotal} fallback={<EyeOff class="w-3.5 h-3.5" />}>
+                                <Calculator class="w-3.5 h-3.5" />
+                            </Show>
+                        </button>
+                        <button
+                            onClick={() => props.onDelete(props.modifier.id)}
+                            class="p-1.5 text-muted-foreground/40 hover:text-destructive hover:bg-destructive/10 rounded-lg transition-all"
+                        >
+                            <Trash2 class="w-3.5 h-3.5" />
+                        </button>
+                    </div>
+                </div>
+            </div>
+        );
+    }
+
+    if (isComputed()) {
+        return (
+            <div class="rounded-2xl border border-border/60 bg-background/70 p-4 space-y-3">
+                <div class="flex items-start justify-between gap-4">
+                    <div class="min-w-0 flex-1 space-y-2">
+                        <div class="flex items-center gap-3">
+                            <input
+                                type="text"
+                                title={module().description}
+                                value={props.modifier.name}
+                                onInput={(e) => props.onUpdate(props.modifier.id, { name: e.currentTarget.value })}
+                                class="bg-transparent border-none outline-none text-sm font-semibold text-foreground focus:ring-0 py-0.5 w-48"
+                                placeholder="Modifier Name"
+                            />
+                            <span class="rounded-full bg-primary/10 px-2 py-0.5 text-[9px] font-black uppercase tracking-[0.2em] text-primary">
+                                Legacy Modifier
+                            </span>
+                        </div>
+
+                        <div class="min-h-[1rem] text-[10px] font-bold uppercase tracking-widest">
+                            <Show
+                                when={!computedStatus().error}
+                                fallback={<span class="text-destructive">{computedStatus().error}</span>}
+                            >
+                                <span class="text-primary/70">Existing computed modifier remains supported</span>
+                            </Show>
+                        </div>
+                    </div>
+
+                    <div class="flex items-center gap-2">
+                        <button
+                            onClick={() => props.onUpdate(props.modifier.id, { includeInTotal: !props.modifier.includeInTotal })}
+                            class={`p-1.5 rounded-lg transition-all ${props.modifier.includeInTotal ? 'text-primary' : 'text-muted-foreground/30'}`}
+                            title={props.modifier.includeInTotal ? 'Included' : 'Excluded'}
+                        >
+                            <Show when={props.modifier.includeInTotal} fallback={<EyeOff class="w-3.5 h-3.5" />}>
+                                <Calculator class="w-3.5 h-3.5" />
+                            </Show>
+                        </button>
+                        <button
+                            onClick={() => props.onDelete(props.modifier.id)}
+                            class="p-1.5 text-muted-foreground/40 hover:text-destructive hover:bg-destructive/10 rounded-lg transition-all"
+                        >
+                            <Trash2 class="w-3.5 h-3.5" />
+                        </button>
+                    </div>
+                </div>
+            </div>
+        );
+    }
+
     return (
         <div class="group flex items-center justify-between py-2 px-1 hover:bg-primary/5 rounded-xl transition-all">
             <div class="flex items-center gap-3">
-                {/* Name */}
                 <input
                     type="text"
                     title={module().description}
@@ -32,7 +257,6 @@ const ModifierRow: Component<ModifierRowProps> = (props) => {
                     placeholder="Modifier Name"
                 />
 
-                {/* Type Toggles - Visible on hover */}
                 <div class="flex items-center gap-1 opacity-0 group-hover:opacity-100 transition-opacity">
                     <button
                         onClick={() => props.onUpdate(props.modifier.id, { valueType: 'percent' })}
@@ -59,13 +283,12 @@ const ModifierRow: Component<ModifierRowProps> = (props) => {
             </div>
 
             <div class="flex items-center gap-4">
-                {/* Value Input */}
                 <div class="flex items-center gap-2">
                     <NumericInput
                         value={props.modifier.value}
                         onUpdate={(val) => props.onUpdate(props.modifier.id, { value: val })}
                         class="w-20 text-right text-sm border-b border-dashed border-border focus:border-primary outline-none bg-transparent text-primary font-medium"
-                        placeholder={props.modifier.moduleId === 'man-hours' ? "Factor" : "0.00"}
+                        placeholder={props.modifier.moduleId === 'man-hours' ? 'Factor' : '0.00'}
                     />
                     <Show when={(props.modifier.valueType === 'unit' && props.modifier.unitLabel) || props.modifier.moduleId === 'man-hours'}>
                         <span class="text-[10px] font-bold text-primary/60">
@@ -74,14 +297,12 @@ const ModifierRow: Component<ModifierRowProps> = (props) => {
                     </Show>
                 </div>
 
-                {/* Calculated Result */}
                 <div class="w-28 text-right flex items-center justify-end gap-1.5">
                     <span class={`text-sm font-medium transition-colors ${props.modifier.includeInTotal ? 'text-foreground' : 'text-muted-foreground/40'}`}>
                         {props.modifier.moduleId === 'man-hours' ? '' : '$'}{formatNumber(props.calculatedValue)}
                         {props.modifier.moduleId === 'man-hours' ? ' hrs' : ''}
                     </span>
-                    
-                    {/* Active/Draft Toggle */}
+
                     <button
                         onClick={() => props.onUpdate(props.modifier.id, { includeInTotal: !props.modifier.includeInTotal })}
                         class={`p-1 rounded-md transition-all ${props.modifier.includeInTotal ? 'text-primary' : 'text-muted-foreground/30'}`}
@@ -93,7 +314,6 @@ const ModifierRow: Component<ModifierRowProps> = (props) => {
                     </button>
                 </div>
 
-                {/* Delete */}
                 <button
                     onClick={() => props.onDelete(props.modifier.id)}
                     class="p-1 opacity-0 group-hover:opacity-100 text-muted-foreground/30 hover:text-destructive hover:bg-destructive/10 rounded-lg transition-all"
diff --git a/src/components/PrintEstimate.tsx b/src/components/PrintEstimate.tsx
index a004de5..4df4aca 100644
--- a/src/components/PrintEstimate.tsx
+++ b/src/components/PrintEstimate.tsx
@@ -4,6 +4,7 @@ import type { Scope, SubScope, EstimateItem, JobInfo } from '../types';
 import { NOTICE_TO_OWNERS } from '../notice-to-owners';
 import { COMPANY_NAME, COMPANY_ADDRESS, COMPANY_PHONE, COMPANY_EMAIL } from '../company-info';
 import { ModifierRegistry } from '../utils/modifier-registry';
+import { getEffectiveItemPricing, getItemsPricingTotals } from '../utils/pricing';
 
 interface PrintEstimateProps {
     scopes: Scope[];
@@ -44,10 +45,13 @@ const PrintEstimate: Component<PrintEstimateProps> = (props) => {
         if (!scope) return 0;
 
         props.items.filter((i: EstimateItem) => i.scopeId === scopeId).forEach((item: EstimateItem) => {
-            const base = item.quantity * item.unitPrice;
-            scopeSubtotal += base;
-            scopeMarkup += item.markupType === 'percent' ? base * (item.markup / 100) : item.markup;
-            scopeContingency += item.contingencyType === 'percent' ? base * (item.contingency / 100) : item.contingency;
+            const modifiers = item.subScopeId
+                ? (props.subScopes.find(subScope => subScope.id === item.subScopeId)?.modifiers || [])
+                : [];
+            const pricing = getEffectiveItemPricing(item, modifiers);
+            scopeSubtotal += pricing.effectiveSubtotal;
+            scopeMarkup += pricing.markupAmount;
+            scopeContingency += pricing.contingencyAmount;
         });
 
         const mgmtFee = scope.useManagementLogic === 'percent'
@@ -63,12 +67,7 @@ const PrintEstimate: Component<PrintEstimateProps> = (props) => {
         
         scopeSubScopes.forEach(ss => {
             const ssItems = props.items.filter(i => i.subScopeId === ss.id);
-            const ssTotalWithMarkup = ssItems.reduce((sum, item) => {
-                const base = item.quantity * item.unitPrice;
-                const markup = item.markupType === 'percent' ? base * (item.markup / 100) : item.markup;
-                const contingency = item.contingencyType === 'percent' ? base * (item.contingency / 100) : item.contingency;
-                return sum + base + markup + contingency;
-            }, 0);
+            const ssTotalWithMarkup = getItemsPricingTotals(ssItems, ss.modifiers || []).total;
 
             (ss.modifiers || []).forEach(m => {
                 if (!m.includeInTotal) return;
@@ -95,7 +94,13 @@ const PrintEstimate: Component<PrintEstimateProps> = (props) => {
         };
     };
 
-    const getItemSubtotal = (item: EstimateItem) => item.quantity * item.unitPrice;
+    const getItemPricing = (item: EstimateItem) => {
+        const modifiers = item.subScopeId
+            ? (props.subScopes.find(subScope => subScope.id === item.subScopeId)?.modifiers || [])
+            : [];
+        return getEffectiveItemPricing(item, modifiers);
+    };
+    const getItemSubtotal = (item: EstimateItem) => getItemPricing(item).effectiveSubtotal;
     const getManagerScopeVisibleTotal = (scopeId: string) =>
         props.items
             .filter((item: EstimateItem) => item.scopeId === scopeId)
@@ -274,8 +279,8 @@ const PrintEstimate: Component<PrintEstimateProps> = (props) => {
                                                             <div class="grid grid-cols-12 gap-3 px-3 py-2 text-xs border-t border-border/20 items-start">
                                                                 <div class="col-span-2 font-bold text-foreground">Scope Level</div>
                                                                 <div class="col-span-6 text-foreground/90">{item.description}</div>
-                                                                <div class="col-span-1 text-right text-foreground">{item.quantity}</div>
-                                                                <div class="col-span-1 text-right text-foreground">${props.formatNumber(item.unitPrice)}</div>
+                                                                <div class="col-span-1 text-right text-foreground">{getItemPricing(item).effectiveQuantity}</div>
+                                                                <div class="col-span-1 text-right text-foreground">${props.formatNumber(getItemPricing(item).effectiveUnitPrice)}</div>
                                                                 <div class="col-span-2 text-right font-bold text-foreground">${props.formatNumber(getItemSubtotal(item))}</div>
                                                             </div>
                                                         )}
@@ -294,8 +299,8 @@ const PrintEstimate: Component<PrintEstimateProps> = (props) => {
                                                                 <div class="grid grid-cols-12 gap-3 px-3 py-2 text-xs border-t border-border/20 items-start">
                                                                     <div class="col-span-2 font-bold text-foreground">{entry.subScope.name}</div>
                                                                     <div class="col-span-6 text-foreground/90">{item.description}</div>
-                                                                    <div class="col-span-1 text-right text-foreground">{item.quantity}</div>
-                                                                    <div class="col-span-1 text-right text-foreground">${props.formatNumber(item.unitPrice)}</div>
+                                                                    <div class="col-span-1 text-right text-foreground">{getItemPricing(item).effectiveQuantity}</div>
+                                                                    <div class="col-span-1 text-right text-foreground">${props.formatNumber(getItemPricing(item).effectiveUnitPrice)}</div>
                                                                     <div class="col-span-2 text-right font-bold text-foreground">${props.formatNumber(getItemSubtotal(item))}</div>
                                                                 </div>
                                                             )}
diff --git a/src/components/ScopeCard.tsx b/src/components/ScopeCard.tsx
index d25f770..b6e74f2 100644
--- a/src/components/ScopeCard.tsx
+++ b/src/components/ScopeCard.tsx
@@ -11,6 +11,7 @@ import { ModifierRegistry } from '../utils/modifier-registry';
 import { appStore } from '../store/appStore';
 import { SupplierDropdown } from './ui/SupplierDropdown';
 import ScopeTextTemplateModal from './ScopeTextTemplateModal';
+import { getItemsPricingTotals } from '../utils/pricing';
 
 interface ScopeCardProps {
     scope: Scope;
@@ -51,20 +52,28 @@ const ScopeCard: Component<ScopeCardProps> = (props) => {
     const scopeItems = createMemo(() => props.items.filter(i => !i.subScopeId));
 
     const totals = createMemo(() => {
-        let subtotal = 0;
-        let markup = 0;
-        let contingency = 0;
-        let totalQuantity = 0;
+        const scopeLevelTotals = getItemsPricingTotals(scopeItems(), []);
+        let subtotal = scopeLevelTotals.subtotal;
+        let markup = scopeLevelTotals.markup;
+        let contingency = scopeLevelTotals.contingency;
+        let totalQuantity = scopeLevelTotals.quantity;
 
-        props.items.forEach(item => {
-            const base = item.quantity * item.unitPrice;
-            subtotal += base;
-            totalQuantity += item.quantity;
-            markup += item.markupType === 'percent' ? base * (item.markup / 100) : item.markup;
-            contingency += item.contingencyType === 'percent' ? base * (item.contingency / 100) : item.contingency;
+        let modifiersTotal = 0;
+        props.subScopes.forEach(ss => {
+            const ssItems = props.items.filter(i => i.subScopeId === ss.id);
+            const ssTotals = getItemsPricingTotals(ssItems, ss.modifiers || []);
+            subtotal += ssTotals.subtotal;
+            markup += ssTotals.markup;
+            contingency += ssTotals.contingency;
+            totalQuantity += ssTotals.quantity;
+
+            (ss.modifiers || []).forEach(m => {
+                if (!m.includeInTotal) return;
+                modifiersTotal += ModifierRegistry.calculate(m, ssTotals.total, ssItems);
+            });
         });
 
-        // Add Management and Delivery
+        // Add Management and Delivery after all scope and sub-scope item totals are accounted for.
         const mgmtTotal = props.scope.useManagementLogic === 'percent'
             ? subtotal * (props.scope.managementFee / 100)
             : props.scope.managementFee;
@@ -73,22 +82,6 @@ const ScopeCard: Component<ScopeCardProps> = (props) => {
             ? subtotal * (props.scope.deliveryFee / 100)
             : props.scope.deliveryFee;
 
-        let modifiersTotal = 0;
-        props.subScopes.forEach(ss => {
-            const ssItems = props.items.filter(i => i.subScopeId === ss.id);
-            const ssTotalWithMarkup = ssItems.reduce((sum, item) => {
-                const base = item.quantity * item.unitPrice;
-                const markup = item.markupType === 'percent' ? base * (item.markup / 100) : item.markup;
-                const contingency = item.contingencyType === 'percent' ? base * (item.contingency / 100) : item.contingency;
-                return sum + base + markup + contingency;
-            }, 0);
-
-            (ss.modifiers || []).forEach(m => {
-                if (!m.includeInTotal) return;
-                modifiersTotal += ModifierRegistry.calculate(m, ssTotalWithMarkup, ssItems);
-            });
-        });
-
         return {
             subtotal,
             markup,
diff --git a/src/components/SubScopeCard.tsx b/src/components/SubScopeCard.tsx
index a73eb7b..b3a7b26 100644
--- a/src/components/SubScopeCard.tsx
+++ b/src/components/SubScopeCard.tsx
@@ -6,6 +6,7 @@ import LazyItem from './LazyItem';
 import ModifierRow from './ModifierRow';
 import { appStore } from '../store/appStore';
 import { ModifierRegistry, MODIFIER_MODULES } from '../utils/modifier-registry';
+import { getItemsPricingTotals } from '../utils/pricing';
 
 interface SubScopeCardProps {
     subScope: SubScope;
@@ -36,28 +37,20 @@ const SubScopeCard: Component<SubScopeCardProps> = (props) => {
     const subScopeItems = () => props.items.filter(item => item.subScopeId === props.subScope.id);
     
     const totals = createMemo(() => {
-        const itemTotals = props.items.reduce((acc, item) => {
-            const base = item.quantity * item.unitPrice;
-            const markup = item.markupType === 'percent' ? base * (item.markup / 100) : item.markup;
-            const contingency = item.contingencyType === 'percent' ? base * (item.contingency / 100) : item.contingency;
-            return {
-                amount: acc.amount + base + markup + contingency,
-                quantity: acc.quantity + item.quantity
-            };
-        }, { amount: 0, quantity: 0 });
-
-        let modifiedAmount = itemTotals.amount;
         const modifiers = props.subScope.modifiers || [];
+        const itemTotals = getItemsPricingTotals(props.items, modifiers);
+
+        let modifiedAmount = itemTotals.total;
         
         modifiers.forEach(m => {
             if (!m.includeInTotal) return;
-            modifiedAmount += ModifierRegistry.calculate(m, itemTotals.amount, subScopeItems());
+            modifiedAmount += ModifierRegistry.calculate(m, itemTotals.total, subScopeItems());
         });
 
         return {
             amount: modifiedAmount,
             quantity: itemTotals.quantity,
-            baseAmount: itemTotals.amount
+            baseAmount: itemTotals.total
         };
     });
 
@@ -220,6 +213,7 @@ const SubScopeCard: Component<SubScopeCardProps> = (props) => {
                                         onToggleSelection={props.onToggleSelection}
                                         hideColumns={props.hideColumns}
                                         activeSupplier={props.scopeSupplier}
+                                        subScopeModifiers={props.subScope.modifiers}
                                     />
                                 </LazyItem>
                             )}
@@ -236,7 +230,7 @@ const SubScopeCard: Component<SubScopeCardProps> = (props) => {
                                     {(modifier) => (
                                         <ModifierRow
                                             modifier={modifier}
-                                            calculatedValue={ModifierRegistry.calculateDisplay(modifier, totals().baseAmount, subScopeItems())}
+                                            calculatedValue={ModifierRegistry.calculateDisplay(modifier, totals().baseAmount, subScopeItems(), props.subScope.modifiers || [])}
                                             onUpdate={(id, updates) => appStore.updateModifier(props.subScope.id, id, updates)}
                                             onDelete={(id) => appStore.removeModifier(props.subScope.id, id)}
                                         />
diff --git a/src/components/estimate-builder/useEstimateCalculations.ts b/src/components/estimate-builder/useEstimateCalculations.ts
index c970d15..abd2018 100644
--- a/src/components/estimate-builder/useEstimateCalculations.ts
+++ b/src/components/estimate-builder/useEstimateCalculations.ts
@@ -2,6 +2,7 @@ import { createMemo } from 'solid-js';
 import type { Accessor } from 'solid-js';
 import { appStore } from '../../store/appStore';
 import { ModifierRegistry } from '../../utils/modifier-registry';
+import { getEffectiveItemPricing, getItemsPricingTotals } from '../../utils/pricing';
 
 export function useEstimateCalculations(selectedIds: Accessor<string[]>) {
     const items = appStore.estimateItems;
@@ -15,15 +16,17 @@ export function useEstimateCalculations(selectedIds: Accessor<string[]>) {
         let contingency = 0;
         let fees = 0;
         const scopeSubtotals = new Map<string, number>();
+        const subScopes = appStore.subScopes;
+        const subScopeById = new Map(subScopes.map(subScope => [subScope.id, subScope]));
 
         items.forEach(item => {
-            const base = item.quantity * item.unitPrice;
-            subtotal += base;
-            markup += item.markupType === 'percent' ? base * (item.markup / 100) : item.markup;
-            contingency += item.contingencyType === 'percent' ? base * (item.contingency / 100) : item.contingency;
+            const pricing = getEffectiveItemPricing(item, item.subScopeId ? (subScopeById.get(item.subScopeId)?.modifiers || []) : []);
+            subtotal += pricing.effectiveSubtotal;
+            markup += pricing.markupAmount;
+            contingency += pricing.contingencyAmount;
 
             if (item.scopeId) {
-                scopeSubtotals.set(item.scopeId, (scopeSubtotals.get(item.scopeId) || 0) + base);
+                scopeSubtotals.set(item.scopeId, (scopeSubtotals.get(item.scopeId) || 0) + pricing.effectiveSubtotal);
             }
         });
 
@@ -40,17 +43,10 @@ export function useEstimateCalculations(selectedIds: Accessor<string[]>) {
         });
 
         let modifiersTotal = 0;
-        const subScopes = appStore.subScopes;
         
         subScopes.forEach(subScope => {
-            const scopeId = subScope.id;
-            const subScopeItems = items.filter(i => i.subScopeId === scopeId); // Wait, subScope.id is compared to item.subScopeId
-            const subScopeTotalWithMarkup = subScopeItems.reduce((sum, item) => {
-                const base = item.quantity * item.unitPrice;
-                const markup = item.markupType === 'percent' ? base * (item.markup / 100) : item.markup;
-                const contingency = item.contingencyType === 'percent' ? base * (item.contingency / 100) : item.contingency;
-                return sum + base + markup + contingency;
-            }, 0);
+            const subScopeItems = items.filter(i => i.subScopeId === subScope.id);
+            const subScopeTotalWithMarkup = getItemsPricingTotals(subScopeItems, subScope.modifiers || []).total;
             
             (subScope.modifiers || []).forEach(m => {
                 if (!m.includeInTotal) return;
@@ -86,19 +82,18 @@ export function useEstimateCalculations(selectedIds: Accessor<string[]>) {
 
     const selectionTotals = createMemo(() => {
         const selected = items.filter(i => selectedIds().includes(i.id));
+        const subScopeById = new Map(appStore.subScopes.map(subScope => [subScope.id, subScope]));
         let qty = 0, price = 0, sub = 0, mark = 0, cont = 0, tot = 0;
 
         selected.forEach(item => {
-            const base = item.quantity * item.unitPrice;
-            const markupAmt = item.markupType === 'percent' ? base * (item.markup / 100) : item.markup;
-            const contingencyAmt = item.contingencyType === 'percent' ? base * (item.contingency / 100) : item.contingency;
+            const pricing = getEffectiveItemPricing(item, item.subScopeId ? (subScopeById.get(item.subScopeId)?.modifiers || []) : []);
 
-            qty += item.quantity;
-            price += item.unitPrice;
-            sub += base;
-            mark += markupAmt;
-            cont += contingencyAmt;
-            tot += base + markupAmt + contingencyAmt;
+            qty += pricing.effectiveQuantity;
+            price += pricing.effectiveUnitPrice;
+            sub += pricing.effectiveSubtotal;
+            mark += pricing.markupAmount;
+            cont += pricing.contingencyAmount;
+            tot += pricing.total;
         });
 
         return {
diff --git a/src/store/appStore.ts b/src/store/appStore.ts
index 09cdbdd..220e456 100644
--- a/src/store/appStore.ts
+++ b/src/store/appStore.ts
@@ -84,8 +84,12 @@ export const appStore = {
             value: module.defaultValue,
             valueType: module.defaultValueType,
             unitLabel: module.defaultUnitLabel,
-            type: module.id as any, // Temporary cast
-            includeInTotal: module.id !== 'man-hours'
+            type: module.id as Modifier['type'],
+            includeInTotal: module.id !== 'man-hours',
+            presetId: module.defaultPresetId,
+            targetField: module.defaultTargetField,
+            expression: module.defaultExpression,
+            parameters: module.defaultParameters ? { ...module.defaultParameters } : undefined
         };
 
         setSubScopes(s => s.id === subScopeId, produce((ss) => {
@@ -130,8 +134,12 @@ export const appStore = {
             value: module.defaultValue,
             valueType: module.defaultValueType,
             unitLabel: module.defaultUnitLabel,
-            type: module.id as any,
-            includeInTotal: module.id !== 'man-hours'
+            type: module.id as Modifier['type'],
+            includeInTotal: module.id !== 'man-hours',
+            presetId: module.defaultPresetId,
+            targetField: module.defaultTargetField,
+            expression: module.defaultExpression,
+            parameters: module.defaultParameters ? { ...module.defaultParameters } : undefined
         };
         setActiveTemplateModifiers(prev => [...prev, newModifier]);
     },
diff --git a/src/types.ts b/src/types.ts
index 46b7cf9..eb8a9fe 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -16,7 +16,9 @@ export interface Scope {
     supplier?: string;
 }
 
-export type ModifierType = 'tax' | 'man-hours' | 'custom';
+export type ModifierType = 'tax' | 'man-hours' | 'adjustment' | 'computed-field' | 'prevailing-wage' | 'custom-calculation' | 'custom';
+export type ModifierPresetId = 'prevailing-wage' | 'custom';
+export type ModifierTargetField = 'unitPrice' | 'quantity' | 'subtotal';
 
 export interface Modifier {
     id: string;
@@ -27,6 +29,10 @@ export interface Modifier {
     type: ModifierType;
     unitLabel?: string; // e.g. "hrs" for man-hours
     includeInTotal: boolean;
+    presetId?: ModifierPresetId;
+    targetField?: ModifierTargetField;
+    expression?: string;
+    parameters?: Record<string, number>;
 }
 
 export interface SubScope {
diff --git a/src/utils/modifier-registry.ts b/src/utils/modifier-registry.ts
index 0a54ceb..9b2d192 100644
--- a/src/utils/modifier-registry.ts
+++ b/src/utils/modifier-registry.ts
@@ -1,4 +1,12 @@
-import type { Modifier, EstimateItem } from '../types';
+import type { Modifier, EstimateItem, ModifierTargetField } from '../types';
+import {
+    CUSTOM_CALC_DEFAULT_EXPRESSION,
+    getComputedModifierStatus,
+    getEffectiveItemPricing,
+    PREVAILING_WAGE_DEFAULT_EXPRESSION,
+    PREVAILING_WAGE_DEFAULT_PARAMETERS,
+    resolveModifierModuleId
+} from './pricing';
 
 export interface ModifierModule {
     id: string;
@@ -8,12 +16,16 @@ export interface ModifierModule {
     defaultValue: number;
     defaultValueType: 'percent' | 'amount' | 'unit';
     defaultUnitLabel?: string;
+    defaultPresetId?: 'prevailing-wage' | 'custom';
+    defaultTargetField?: ModifierTargetField;
+    defaultExpression?: string;
+    defaultParameters?: Record<string, number>;
     calculate: (modifier: Modifier, subScopeTotalWithMarkup: number, subScopeItems: EstimateItem[]) => number;
-    calculateDisplay?: (modifier: Modifier, subScopeTotalWithMarkup: number, subScopeItems: EstimateItem[]) => number;
+    calculateDisplay?: (modifier: Modifier, subScopeTotalWithMarkup: number, subScopeItems: EstimateItem[], subScopeModifiers?: Modifier[]) => number;
 }
 
-const getPreMarkupSubtotal = (items: EstimateItem[]) => {
-    return items.reduce((sum, item) => sum + item.quantity * item.unitPrice, 0);
+const getPreMarkupSubtotal = (items: EstimateItem[], modifiers: Modifier[] = []) => {
+    return items.reduce((sum, item) => sum + getEffectiveItemPricing(item, modifiers).effectiveSubtotal, 0);
 };
 
 const TaxModule: ModifierModule = {
@@ -38,10 +50,10 @@ const ManHoursModule: ModifierModule = {
     defaultValueType: 'unit',
     defaultUnitLabel: 'factor',
     calculate: () => 0,
-    calculateDisplay: (m, _, items) => {
+    calculateDisplay: (m, _, items, subScopeModifiers = []) => {
         const factor = m.value || 1;
         if (factor === 0) return 0;
-        const subtotal = getPreMarkupSubtotal(items);
+        const subtotal = getPreMarkupSubtotal(items, subScopeModifiers);
         return subtotal / factor;
     }
 };
@@ -59,23 +71,62 @@ const SimpleAdjustmentModule: ModifierModule = {
     }
 };
 
+const PrevailingWageModule: ModifierModule = {
+    id: 'prevailing-wage',
+    name: 'Prevailing Wage',
+    description: 'Scales each item price by the prevailing wage multiplier.',
+    defaultLabel: 'Prevailing Wage',
+    defaultValue: 0,
+    defaultValueType: 'unit',
+    defaultPresetId: 'prevailing-wage',
+    defaultTargetField: 'unitPrice',
+    defaultExpression: PREVAILING_WAGE_DEFAULT_EXPRESSION,
+    defaultParameters: { ...PREVAILING_WAGE_DEFAULT_PARAMETERS },
+    calculate: () => 0,
+    calculateDisplay: (modifier) => getComputedModifierStatus(modifier).multiplier || 0
+};
+
+const CustomCalculationModule: ModifierModule = {
+    id: 'custom-calculation',
+    name: 'Custom Math',
+    description: 'Applies a custom expression using price, quantity, and subtotal variables.',
+    defaultLabel: 'Custom Math',
+    defaultValue: 0,
+    defaultValueType: 'unit',
+    defaultPresetId: 'custom',
+    defaultTargetField: 'unitPrice',
+    defaultExpression: CUSTOM_CALC_DEFAULT_EXPRESSION,
+    calculate: () => 0,
+    calculateDisplay: () => 0
+};
+
 export const MODIFIER_MODULES: ModifierModule[] = [
     TaxModule,
     ManHoursModule,
-    SimpleAdjustmentModule
+    SimpleAdjustmentModule,
+    PrevailingWageModule,
+    CustomCalculationModule
 ];
 
+const getModuleByResolvedId = (id: string) => MODIFIER_MODULES.find(m => m.id === id) || SimpleAdjustmentModule;
+
 export const ModifierRegistry = {
-    getModule: (id: string) => MODIFIER_MODULES.find(m => m.id === id) || SimpleAdjustmentModule,
+    getModule: (id: string, modifier?: Modifier) => {
+        if (id === 'computed-field' && modifier) {
+            return getModuleByResolvedId(resolveModifierModuleId(modifier));
+        }
+
+        return getModuleByResolvedId(id);
+    },
     
     calculate: (modifier: Modifier, baseTotal: number, items: EstimateItem[]) => {
-        const module = ModifierRegistry.getModule(modifier.moduleId);
+        const module = ModifierRegistry.getModule(modifier.moduleId, modifier);
         return module.calculate(modifier, baseTotal, items);
     },
 
-    calculateDisplay: (modifier: Modifier, baseTotal: number, items: EstimateItem[]) => {
-        const module = ModifierRegistry.getModule(modifier.moduleId);
-        if (module.calculateDisplay) return module.calculateDisplay(modifier, baseTotal, items);
+    calculateDisplay: (modifier: Modifier, baseTotal: number, items: EstimateItem[], subScopeModifiers: Modifier[] = []) => {
+        const module = ModifierRegistry.getModule(modifier.moduleId, modifier);
+        if (module.calculateDisplay) return module.calculateDisplay(modifier, baseTotal, items, subScopeModifiers);
         return module.calculate(modifier, baseTotal, items);
     }
 };
diff --git a/src/utils/pricing.ts b/src/utils/pricing.ts
new file mode 100644
index 0000000..327870c
--- /dev/null
+++ b/src/utils/pricing.ts
@@ -0,0 +1,412 @@
+import type { EstimateItem, Modifier, ModifierTargetField } from '../types';
+
+export const PREVAILING_WAGE_DEFAULT_PARAMETERS = {
+    baseRate: 30,
+    prevailingRate: 50
+} as const;
+
+export const PREVAILING_WAGE_DEFAULT_EXPRESSION = 'price * multiplier';
+export const CUSTOM_CALC_DEFAULT_EXPRESSION = 'price';
+
+export const TARGET_FIELD_LABELS: Record<ModifierTargetField, string> = {
+    unitPrice: 'Price',
+    quantity: 'Quantity',
+    subtotal: 'Subtotal'
+};
+
+const PREVIEW_ITEM: EstimateItem = {
+    id: '__preview__',
+    description: 'Preview',
+    quantity: 1,
+    unitPrice: 1,
+    markup: 0,
+    markupType: 'percent',
+    contingency: 0,
+    contingencyType: 'percent'
+};
+
+type Token =
+    | { type: 'number'; value: number }
+    | { type: 'identifier'; value: string }
+    | { type: 'operator'; value: '+' | '-' | '*' | '/' }
+    | { type: 'paren'; value: '(' | ')' };
+
+interface ComputedItemState {
+    quantity: number;
+    unitPrice: number;
+}
+
+export interface ComputedModifierStatus {
+    parameters: Record<string, number>;
+    expression: string;
+    targetField: ModifierTargetField;
+    multiplier?: number;
+    error?: string;
+}
+
+export interface EffectiveItemPricing {
+    baseQuantity: number;
+    effectiveQuantity: number;
+    baseUnitPrice: number;
+    effectiveUnitPrice: number;
+    baseSubtotal: number;
+    effectiveSubtotal: number;
+    markupAmount: number;
+    contingencyAmount: number;
+    total: number;
+    hasAdjustedQuantity: boolean;
+    hasAdjustedUnitPrice: boolean;
+    hasAdjustedSubtotal: boolean;
+    hasDirectQuantityAdjustment: boolean;
+    hasDirectUnitPriceAdjustment: boolean;
+    hasDirectSubtotalAdjustment: boolean;
+}
+
+export interface ItemTotals {
+    subtotal: number;
+    markup: number;
+    contingency: number;
+    total: number;
+    quantity: number;
+}
+
+export const resolveModifierModuleId = (modifier: Modifier) => {
+    if (modifier.moduleId === 'computed-field') {
+        return modifier.presetId === 'custom' ? 'custom-calculation' : 'prevailing-wage';
+    }
+
+    return modifier.moduleId;
+};
+
+export const isPrevailingWageModifier = (modifier: Modifier) => resolveModifierModuleId(modifier) === 'prevailing-wage';
+export const isCustomCalculationModifier = (modifier: Modifier) => resolveModifierModuleId(modifier) === 'custom-calculation';
+export const isComputedFieldModifier = (modifier: Modifier) => isPrevailingWageModifier(modifier) || isCustomCalculationModifier(modifier);
+
+export const getResolvedTargetField = (modifier: Modifier): ModifierTargetField => {
+    if (isPrevailingWageModifier(modifier)) return 'unitPrice';
+    return modifier.targetField || 'unitPrice';
+};
+
+export const getComputedModifierParameters = (modifier: Modifier) => {
+    const defaults: Record<string, number> = isPrevailingWageModifier(modifier)
+        ? PREVAILING_WAGE_DEFAULT_PARAMETERS
+        : {};
+
+    return {
+        ...defaults,
+        ...(modifier.parameters || {})
+    };
+};
+
+export const getModifierExpression = (modifier: Modifier) => {
+    if (isPrevailingWageModifier(modifier)) {
+        return PREVAILING_WAGE_DEFAULT_EXPRESSION;
+    }
+
+    return modifier.expression?.trim() || CUSTOM_CALC_DEFAULT_EXPRESSION;
+};
+
+const tokenizeExpression = (expression: string): Token[] => {
+    const tokens: Token[] = [];
+    let index = 0;
+
+    while (index < expression.length) {
+        const char = expression[index];
+
+        if (/\s/.test(char)) {
+            index += 1;
+            continue;
+        }
+
+        if (/[+\-*/]/.test(char)) {
+            tokens.push({ type: 'operator', value: char as '+' | '-' | '*' | '/' });
+            index += 1;
+            continue;
+        }
+
+        if (char === '(' || char === ')') {
+            tokens.push({ type: 'paren', value: char });
+            index += 1;
+            continue;
+        }
+
+        if (/\d|\./.test(char)) {
+            let end = index + 1;
+            while (end < expression.length && /[\d.]/.test(expression[end])) end += 1;
+            const raw = expression.slice(index, end);
+            const value = Number.parseFloat(raw);
+            if (!Number.isFinite(value)) {
+                throw new Error(`Invalid number "${raw}".`);
+            }
+            tokens.push({ type: 'number', value });
+            index = end;
+            continue;
+        }
+
+        if (/[A-Za-z_]/.test(char)) {
+            let end = index + 1;
+            while (end < expression.length && /[A-Za-z0-9_]/.test(expression[end])) end += 1;
+            tokens.push({ type: 'identifier', value: expression.slice(index, end) });
+            index = end;
+            continue;
+        }
+
+        throw new Error(`Unsupported token "${char}".`);
+    }
+
+    return tokens;
+};
+
+const evaluateArithmeticExpression = (expression: string, context: Record<string, number>) => {
+    const trimmedExpression = expression.trim();
+    if (!trimmedExpression) {
+        throw new Error('Expression is required.');
+    }
+
+    const tokens = tokenizeExpression(trimmedExpression);
+    let index = 0;
+
+    const peek = () => tokens[index];
+    const consume = () => tokens[index++];
+
+    const parseExpression = (): number => {
+        let value = parseTerm();
+        while (peek()?.type === 'operator' && (peek()?.value === '+' || peek()?.value === '-')) {
+            const operator = consume().value;
+            const nextValue = parseTerm();
+            value = operator === '+' ? value + nextValue : value - nextValue;
+        }
+        return value;
+    };
+
+    const parseTerm = (): number => {
+        let value = parseFactor();
+        while (peek()?.type === 'operator' && (peek()?.value === '*' || peek()?.value === '/')) {
+            const operator = consume().value;
+            const nextValue = parseFactor();
+            if (operator === '/') {
+                if (nextValue === 0) throw new Error('Division by zero is not allowed.');
+                value /= nextValue;
+            } else {
+                value *= nextValue;
+            }
+        }
+        return value;
+    };
+
+    const parseFactor = (): number => {
+        const token = peek();
+        if (!token) throw new Error('Unexpected end of expression.');
+
+        if (token.type === 'operator' && token.value === '-') {
+            consume();
+            return -parseFactor();
+        }
+
+        if (token.type === 'number') {
+            consume();
+            return token.value;
+        }
+
+        if (token.type === 'identifier') {
+            consume();
+            const value = context[token.value];
+            if (!Number.isFinite(value)) {
+                throw new Error(`Unknown variable "${token.value}".`);
+            }
+            return value;
+        }
+
+        if (token.type === 'paren' && token.value === '(') {
+            consume();
+            const value = parseExpression();
+            const closing = consume();
+            if (!closing || closing.type !== 'paren' || closing.value !== ')') {
+                throw new Error('Missing closing parenthesis.');
+            }
+            return value;
+        }
+
+        throw new Error('Unexpected token in expression.');
+    };
+
+    const value = parseExpression();
+    if (index < tokens.length) {
+        throw new Error('Unexpected trailing token.');
+    }
+    if (!Number.isFinite(value)) {
+        throw new Error('Expression did not produce a finite number.');
+    }
+
+    return value;
+};
+
+const buildModifierContext = (modifier: Modifier, item: EstimateItem, state: ComputedItemState) => {
+    const parameters = getComputedModifierParameters(modifier);
+    const baseRate = parameters.baseRate;
+    const prevailingRate = parameters.prevailingRate;
+
+    if (isPrevailingWageModifier(modifier)) {
+        if (!Number.isFinite(baseRate) || baseRate <= 0) {
+            throw new Error('Base rate must be greater than 0.');
+        }
+        if (!Number.isFinite(prevailingRate)) {
+            throw new Error('Prevailing wage rate must be a valid number.');
+        }
+    }
+
+    const targetField = getResolvedTargetField(modifier);
+    const subtotal = state.quantity * state.unitPrice;
+    const context: Record<string, number> = {
+        value: targetField === 'unitPrice'
+            ? state.unitPrice
+            : targetField === 'quantity'
+                ? state.quantity
+                : subtotal,
+        price: state.unitPrice,
+        quantity: state.quantity,
+        subtotal,
+        basePrice: item.unitPrice,
+        baseQuantity: item.quantity,
+        baseSubtotal: item.quantity * item.unitPrice,
+        markup: item.markup,
+        contingency: item.contingency,
+        ...parameters
+    };
+
+    if (Number.isFinite(baseRate) && baseRate > 0 && Number.isFinite(prevailingRate)) {
+        context.multiplier = prevailingRate / baseRate;
+    }
+
+    return {
+        parameters,
+        targetField,
+        context
+    };
+};
+
+const applyComputedModifierToState = (modifier: Modifier, item: EstimateItem, state: ComputedItemState) => {
+    const expression = getModifierExpression(modifier);
+    const { targetField, context } = buildModifierContext(modifier, item, state);
+    const nextValue = evaluateArithmeticExpression(expression, context);
+
+    if (targetField === 'unitPrice') {
+        return {
+            quantity: state.quantity,
+            unitPrice: nextValue
+        };
+    }
+
+    if (targetField === 'quantity') {
+        return {
+            quantity: nextValue,
+            unitPrice: state.unitPrice
+        };
+    }
+
+    if (state.quantity === 0) {
+        if (nextValue === 0) {
+            return {
+                quantity: state.quantity,
+                unitPrice: 0
+            };
+        }
+
+        throw new Error('Subtotal output requires a non-zero quantity.');
+    }
+
+    return {
+        quantity: state.quantity,
+        unitPrice: nextValue / state.quantity
+    };
+};
+
+export const getComputedModifierStatus = (
+    modifier: Modifier,
+    item: EstimateItem = PREVIEW_ITEM,
+    state: ComputedItemState = { quantity: item.quantity, unitPrice: item.unitPrice }
+): ComputedModifierStatus => {
+    const expression = getModifierExpression(modifier);
+
+    try {
+        const { parameters, targetField, context } = buildModifierContext(modifier, item, state);
+        evaluateArithmeticExpression(expression, context);
+        return {
+            parameters,
+            expression,
+            targetField,
+            multiplier: context.multiplier
+        };
+    } catch (error) {
+        return {
+            parameters: getComputedModifierParameters(modifier),
+            expression,
+            targetField: getResolvedTargetField(modifier),
+            error: error instanceof Error ? error.message : 'Invalid expression.'
+        };
+    }
+};
+
+export const getEffectiveItemPricing = (item: EstimateItem, modifiers: Modifier[] = []): EffectiveItemPricing => {
+    let state: ComputedItemState = {
+        quantity: item.quantity,
+        unitPrice: item.unitPrice
+    };
+    const adjustedTargets = new Set<ModifierTargetField>();
+
+    modifiers.forEach((modifier) => {
+        if (!modifier.includeInTotal || !isComputedFieldModifier(modifier)) return;
+
+        try {
+            state = applyComputedModifierToState(modifier, item, state);
+            adjustedTargets.add(getResolvedTargetField(modifier));
+        } catch {
+            // Invalid computed modifiers are treated as inactive for pricing.
+        }
+    });
+
+    const effectiveSubtotal = state.quantity * state.unitPrice;
+    const markupAmount = item.markupType === 'percent'
+        ? effectiveSubtotal * (item.markup / 100)
+        : item.markup;
+    const contingencyAmount = item.contingencyType === 'percent'
+        ? effectiveSubtotal * (item.contingency / 100)
+        : item.contingency;
+
+    return {
+        baseQuantity: item.quantity,
+        effectiveQuantity: state.quantity,
+        baseUnitPrice: item.unitPrice,
+        effectiveUnitPrice: state.unitPrice,
+        baseSubtotal: item.quantity * item.unitPrice,
+        effectiveSubtotal,
+        markupAmount,
+        contingencyAmount,
+        total: effectiveSubtotal + markupAmount + contingencyAmount,
+        hasAdjustedQuantity: state.quantity !== item.quantity,
+        hasAdjustedUnitPrice: state.unitPrice !== item.unitPrice,
+        hasAdjustedSubtotal: effectiveSubtotal !== item.quantity * item.unitPrice,
+        hasDirectQuantityAdjustment: adjustedTargets.has('quantity'),
+        hasDirectUnitPriceAdjustment: adjustedTargets.has('unitPrice'),
+        hasDirectSubtotalAdjustment: adjustedTargets.has('subtotal')
+    };
+};
+
+export const getItemsPricingTotals = (items: EstimateItem[], modifiers: Modifier[] = []): ItemTotals => {
+    return items.reduce<ItemTotals>((acc, item) => {
+        const pricing = getEffectiveItemPricing(item, modifiers);
+        return {
+            subtotal: acc.subtotal + pricing.effectiveSubtotal,
+            markup: acc.markup + pricing.markupAmount,
+            contingency: acc.contingency + pricing.contingencyAmount,
+            total: acc.total + pricing.total,
+            quantity: acc.quantity + pricing.effectiveQuantity
+        };
+    }, {
+        subtotal: 0,
+        markup: 0,
+        contingency: 0,
+        total: 0,
+        quantity: 0
+    });
+};
diff --git a/src/views/TemplateCreator.tsx b/src/views/TemplateCreator.tsx
index da7744b..8f678db 100644
--- a/src/views/TemplateCreator.tsx
+++ b/src/views/TemplateCreator.tsx
@@ -1,6 +1,6 @@
 import { For, createSignal, createMemo, type Component } from 'solid-js';
 import { FolderOpen, Save, Calculator, Plus } from 'lucide-solid';
-import type { TemplateItem } from '../types';
+import type { EstimateItem, TemplateItem } from '../types';
 import TemplateItemList from '../components/template/TemplateItemList';
 import ModifierRow from '../components/ModifierRow';
 import { ModifierRegistry, MODIFIER_MODULES } from '../utils/modifier-registry';
@@ -8,6 +8,7 @@ import TemplateLoadModal from '../components/template/TemplateLoadModal';
 import { pb, COLLECTIONS } from '../utils/db';
 
 import { appStore } from '../store/appStore';
+import { getItemsPricingTotals } from '../utils/pricing';
 
 const TemplateCreator: Component = () => {
     const templateId = appStore.templateId;
@@ -21,9 +22,12 @@ const TemplateCreator: Component = () => {
     const defaultSubScopeName = appStore.templateSubScopeName;
     const setDefaultSubScopeName = appStore.setTemplateSubScopeName;
 
-    const templateSubtotal = createMemo(() => {
-        return items.reduce((sum, item) => sum + (item.quantity * item.unitPrice), 0);
-    });
+    const templateEstimateItems = createMemo<EstimateItem[]>(() => items.map(item => ({
+        ...item,
+        scopeId: undefined,
+        subScopeId: undefined
+    })));
+    const templateSubtotal = createMemo(() => getItemsPricingTotals(templateEstimateItems(), modifiers).total);
 
     const [showLoadModal, setShowLoadModal] = createSignal(false);
 
@@ -194,7 +198,7 @@ const TemplateCreator: Component = () => {
                             {(modifier) => (
                                 <ModifierRow
                                     modifier={modifier}
-                                    calculatedValue={ModifierRegistry.calculateDisplay(modifier, templateSubtotal(), [])}
+                                    calculatedValue={ModifierRegistry.calculateDisplay(modifier, templateSubtotal(), templateEstimateItems(), modifiers)}
                                     onUpdate={appStore.updateTemplateModifier}
                                     onDelete={appStore.removeTemplateModifier}
                                 />