diff --git a/prisma/migrations/20260718092854_add_product_dimensions/migration.sql b/prisma/migrations/20260718092854_add_product_dimensions/migration.sql
new file mode 100644
index 0000000..0afa805
--- /dev/null
+++ b/prisma/migrations/20260718092854_add_product_dimensions/migration.sql
@@ -0,0 +1,3 @@
+-- AlterTable
+ALTER TABLE "Product" ADD COLUMN     "printAreaHeightMm" INTEGER NOT NULL DEFAULT 280,
+ADD COLUMN     "printAreaWidthMm" INTEGER NOT NULL DEFAULT 200;
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 94ecab1..c6bbb32 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -37,6 +37,8 @@ model Product {
   mockup      String // which SVG mockup component to render, e.g. "tshirt" | "hoodie" | "mug" | "phonecase"
   printArea   String // JSON: {"xPct":..,"yPct":..,"wPct":..,"hPct":..}
   printAreaBack String? // same shape, for the back print area — only used when imageUrlBack is set
+  printAreaWidthMm Int @default(200) // width of the printable area in millimeters
+  printAreaHeightMm Int @default(280) // height of the printable area in millimeters
   imageUrl    String? // optional real product photo — shown instead of the illustration when set
   imageUrlBack String? // optional back-view photo, toggled alongside the front photo
   photoRecolorable Boolean @default(false) // if true, the photo is treated as a grayscale
diff --git a/src/app/admin/orders/[id]/page.tsx b/src/app/admin/orders/[id]/page.tsx
index 201b5f3..c2100d6 100644
--- a/src/app/admin/orders/[id]/page.tsx
+++ b/src/app/admin/orders/[id]/page.tsx
@@ -23,6 +23,12 @@ export default async function OrderDetailPage({ params }: { params: { id: string
         <h1 className="font-display text-3xl">Order</h1>
         <div className="flex items-center gap-3">
           {order.archived && <span className="tag-label">Archived</span>}
+          <a
+            href={`/api/orders/${order.id}/design-spec`}
+            className="tag-label border border-line px-3 py-1.5 hover:border-clay hover:text-clay"
+          >
+            ↓ Download specs
+          </a>
           <form action={order.archived ? unarchiveOrder : archiveOrder}>
             <input type="hidden" name="id" value={order.id} />
             <button type="submit" className="tag-label border border-line px-3 py-1.5 hover:border-clay hover:text-clay">
diff --git a/src/app/api/orders/[id]/design-spec/route.ts b/src/app/api/orders/[id]/design-spec/route.ts
new file mode 100644
index 0000000..0344a40
--- /dev/null
+++ b/src/app/api/orders/[id]/design-spec/route.ts
@@ -0,0 +1,258 @@
+import { NextResponse } from 'next/server';
+import { prisma } from '@/lib/prisma';
+
+export async function GET(req: Request, { params }: { params: { id: string } }) {
+  try {
+    const { id } = params;
+    const order = await prisma.order.findUnique({
+      where: { id },
+      include: { items: true },
+    });
+
+    if (!order) {
+      return NextResponse.json({ error: 'Order not found' }, { status: 404 });
+    }
+
+    const item = order.items[0];
+    if (!item) {
+      return NextResponse.json({ error: 'No items in order' }, { status: 400 });
+    }
+
+    const design = JSON.parse(item.designJson) as { front: any[]; back: any[] };
+    const product = await prisma.product.findUnique({
+      where: { id: item.productId },
+    });
+
+    if (!product) {
+      return NextResponse.json({ error: 'Product not found' }, { status: 404 });
+    }
+
+    // Generate HTML/CSS for a printable spec sheet
+    const printAreaWidthMm = product.printAreaWidthMm || 200;
+    const printAreaHeightMm = product.printAreaHeightMm || 280;
+
+    // Calculate scale factor: pixels to millimeters
+    const DISPLAY = 560; // Same as in DesignCanvas
+    const printArea = JSON.parse(product.printArea) as {
+      xPct: number;
+      yPct: number;
+      wPct: number;
+      hPct: number;
+    };
+
+    const printAreaWidthPx = DISPLAY * (printArea.wPct / 100);
+    const printAreaHeightPx = DISPLAY * (printArea.hPct / 100);
+    const pxPerMm = printAreaWidthPx / printAreaWidthMm;
+
+    // Convert pixel positions to CM
+    const convertToCm = (px: number) => (px / pxPerMm / 10).toFixed(1);
+
+    const html = `
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Design Specification - Order ${order.id}</title>
+  <style>
+    body {
+      font-family: Arial, sans-serif;
+      padding: 20px;
+      max-width: 1000px;
+      margin: 0 auto;
+    }
+    h1 { font-size: 24px; margin-bottom: 10px; }
+    .order-info {
+      background: #f5f5f5;
+      padding: 15px;
+      border-radius: 5px;
+      margin-bottom: 20px;
+    }
+    .order-info p {
+      margin: 5px 0;
+      font-size: 14px;
+    }
+    .spec-section {
+      margin-top: 30px;
+      page-break-inside: avoid;
+    }
+    .spec-section h2 {
+      font-size: 18px;
+      border-bottom: 2px solid #333;
+      padding-bottom: 10px;
+      margin-bottom: 15px;
+    }
+    .mockup-container {
+      text-align: center;
+      margin: 20px 0;
+    }
+    .mockup-image {
+      max-width: 100%;
+      height: auto;
+      border: 1px solid #ddd;
+      margin: 10px 0;
+    }
+    .measurements-table {
+      width: 100%;
+      border-collapse: collapse;
+      margin-top: 15px;
+      font-size: 14px;
+    }
+    .measurements-table th,
+    .measurements-table td {
+      border: 1px solid #ddd;
+      padding: 8px;
+      text-align: left;
+    }
+    .measurements-table th {
+      background: #f0f0f0;
+      font-weight: bold;
+    }
+    .element-type {
+      font-weight: bold;
+      color: #333;
+    }
+    .print-area-info {
+      background: #e8f4f8;
+      padding: 10px;
+      border-radius: 5px;
+      margin: 15px 0;
+      font-size: 13px;
+    }
+    @media print {
+      body { padding: 0; }
+      .spec-section { page-break-inside: avoid; }
+    }
+  </style>
+</head>
+<body>
+  <h1>Design Specification Sheet</h1>
+
+  <div class="order-info">
+    <p><strong>Order ID:</strong> ${order.id}</p>
+    <p><strong>Product:</strong> ${item.productName}</p>
+    <p><strong>Color:</strong> ${item.color} ${item.size ? `| Size: ${item.size}` : ''}</p>
+    <p><strong>Order Date:</strong> ${new Date(order.createdAt).toLocaleDateString()}</p>
+  </div>
+
+  ${design.front && design.front.length > 0 ? `
+  <div class="spec-section">
+    <h2>Front Design</h2>
+
+    <div class="print-area-info">
+      <strong>Printable Area:</strong> ${printAreaWidthMm}mm × ${printAreaHeightMm}mm (${convertToCm(printAreaWidthPx)} cm × ${convertToCm(printAreaHeightPx)} cm)
+    </div>
+
+    ${item.placementPreviewUrl ? `
+      <div class="mockup-container">
+        <p><em>Design on product (reference only)</em></p>
+        <img src="${item.placementPreviewUrl}" alt="Front design placement" class="mockup-image" style="max-height: 400px;">
+      </div>
+    ` : ''}
+
+    <table class="measurements-table">
+      <thead>
+        <tr>
+          <th>Element</th>
+          <th>Type</th>
+          <th>Position (CM)</th>
+          <th>Size (CM)</th>
+          <th>Details</th>
+        </tr>
+      </thead>
+      <tbody>
+        ${(design.front as any[]).map((el, idx) => `
+          <tr>
+            <td>${idx + 1}</td>
+            <td class="element-type">${el.type === 'text' ? '📝 Text' : '🖼️ Image'}</td>
+            <td>X: ${convertToCm(el.x)} | Y: ${convertToCm(el.y)}</td>
+            <td>${el.type === 'image' ? `${convertToCm(el.width)} × ${convertToCm(el.height)}` : 'N/A'}</td>
+            <td>
+              ${el.type === 'text' ? `
+                Font: ${el.fontFamily}, ${Math.round(el.fontSize / pxPerMm * 10 / 10)}pt<br>
+                Color: ${el.fill}<br>
+                Text: "${el.text}"<br>
+                Rotation: ${Math.round(el.rotation)}°
+              ` : `
+                Rotation: ${Math.round(el.rotation)}°
+              `}
+            </td>
+          </tr>
+        `).join('')}
+      </tbody>
+    </table>
+  </div>
+  ` : ''}
+
+  ${design.back && design.back.length > 0 ? `
+  <div class="spec-section">
+    <h2>Back Design</h2>
+
+    <div class="print-area-info">
+      <strong>Printable Area:</strong> ${printAreaWidthMm}mm × ${printAreaHeightMm}mm (${convertToCm(printAreaWidthPx)} cm × ${convertToCm(printAreaHeightPx)} cm)
+    </div>
+
+    ${item.placementPreviewUrlBack ? `
+      <div class="mockup-container">
+        <p><em>Design on product (reference only)</em></p>
+        <img src="${item.placementPreviewUrlBack}" alt="Back design placement" class="mockup-image" style="max-height: 400px;">
+      </div>
+    ` : ''}
+
+    <table class="measurements-table">
+      <thead>
+        <tr>
+          <th>Element</th>
+          <th>Type</th>
+          <th>Position (CM)</th>
+          <th>Size (CM)</th>
+          <th>Details</th>
+        </tr>
+      </thead>
+      <tbody>
+        ${(design.back as any[]).map((el, idx) => `
+          <tr>
+            <td>${idx + 1}</td>
+            <td class="element-type">${el.type === 'text' ? '📝 Text' : '🖼️ Image'}</td>
+            <td>X: ${convertToCm(el.x)} | Y: ${convertToCm(el.y)}</td>
+            <td>${el.type === 'image' ? `${convertToCm(el.width)} × ${convertToCm(el.height)}` : 'N/A'}</td>
+            <td>
+              ${el.type === 'text' ? `
+                Font: ${el.fontFamily}, ${Math.round(el.fontSize / pxPerMm * 10 / 10)}pt<br>
+                Color: ${el.fill}<br>
+                Text: "${el.text}"<br>
+                Rotation: ${Math.round(el.rotation)}°
+              ` : `
+                Rotation: ${Math.round(el.rotation)}°
+              `}
+            </td>
+          </tr>
+        `).join('')}
+      </tbody>
+    </table>
+  </div>
+  ` : ''}
+
+  <div class="spec-section" style="margin-top: 40px; padding-top: 20px; border-top: 1px solid #ccc; font-size: 12px; color: #666;">
+    <p><strong>Notes:</strong></p>
+    <ul>
+      <li>All measurements are in centimeters (CM)</li>
+      <li>Coordinates are measured from top-left of the printable area</li>
+      <li>Print the design files separately for production</li>
+      <li>This specification sheet is for reference and planning only</li>
+    </ul>
+  </div>
+</body>
+</html>
+    `;
+
+    return new NextResponse(html, {
+      headers: {
+        'Content-Type': 'text/html; charset=utf-8',
+        'Content-Disposition': `attachment; filename="design-spec-${order.id}.html"`,
+      },
+    });
+  } catch (err) {
+    console.error('Error generating design spec:', err);
+    return NextResponse.json({ error: 'Failed to generate specification' }, { status: 500 });
+  }
+}