Stained Glass Copper Foil Calculator
Calculate copper foil tape length and rolls needed for stained glass projects by piece count and dimensions.
The copper foil (Tiffany) method of stained glass construction wraps each glass piece with adhesive-backed copper tape before soldering. Calculating foil usage prevents running out mid-project.
Core Formula: Total Foil Length = Sum of all piece perimeters + Overlap allowance
For each piece: Foil per piece = Perimeter of piece + Overlap (typically 0.25–0.5 inches per piece)
Estimating Perimeters by Shape: Since stained glass pieces are irregular, approximate each piece by its closest geometric shape:
| Shape | Perimeter Formula | Example (4" wide) |
|---|---|---|
| Square | 4 × side | 16 inches |
| Rectangle | 2 × (L + W) | varies |
| Triangle | a + b + c (≈ 3 × avg side) | ~12 inches |
| Circle | π × diameter | 12.6 inches |
| Irregular | measure or estimate | varies |
Average Perimeter by Piece Size: A common estimation method uses average piece size:
| Piece Category | Avg Perimeter | Description |
|---|---|---|
| Small (under 3") | 8–10 inches | Detail pieces, eyes, accents |
| Medium (3"–5") | 12–16 inches | Standard panel pieces |
| Large (5"–8") | 18–24 inches | Background, sky sections |
| Very large (8"+) | 26–36 inches | Borders, large fills |
Worked Example — 45-piece suncatcher panel:
- 10 small pieces: 10 × 9" = 90"
- 25 medium pieces: 25 × 14" = 350"
- 10 large pieces: 10 × 21" = 210"
- Subtotal: 650 inches
- Overlap (0.375" per piece × 45): 16.9"
- Waste (5%): 33.3"
- Total: 700 inches ≈ 58.3 feet
Foil Roll Sizes: Standard rolls are 36 yards (108 feet). One roll covers approximately 65–90 medium-sized pieces depending on piece dimensions and foil width.
Foil Width Selection:
- 3/16" (4.8 mm): thin glass, delicate work
- 7/32" (5.6 mm): standard for most projects
- 1/4" (6.4 mm): thick glass, wide solder lines
- 3/8" (9.5 mm): very thick glass, decorative wide lines
Match foil width to glass thickness: foil should wrap around the edge with equal overlap on both sides (about 1/16" per side minimum).