Leather Wallet Pattern Size Calculator
Calculate leather piece dimensions in inches and mm for bifold, trifold, and card slot wallets from card count.
Returns cut dimensions with seam allowances.
Wallet construction needs precise measurements because leather does not stretch or forgive the way fabric does. Every piece has to account for the thickness of the cards, the bills, and the leather itself. Get it wrong and the finished wallet either will not close or will not hold a card securely.
Standard Wallet Dimensions
Credit cards measure 3.375 × 2.125 inches (85.6 × 53.98 mm) worldwide per the ISO/IEC 7810 ID-1 standard. US bills measure 6.14 × 2.61 inches (156 × 66 mm). These are your anchor measurements.
| Wallet Style | Closed Size (W × H) | Open Flat Size | Fold direction |
|---|---|---|---|
| Bifold | 4.25 × 3.5" | 8.5 × 3.5" | side to side |
| Trifold | 3.0 × 3.5" | 9.0 × 3.5" | side to side, twice |
| Card Wallet (slim) | 4.0 × 2.75" | 4.0 × 5.5" | top over bottom |
| Long / Breast Wallet | 7.0 × 3.75" | 7.0 × 7.5" | top over bottom |
That last column matters more than it looks. A bifold gets wider when you open it, so the fold allowance goes on the width. A breast wallet gets taller, so the allowance goes on the height and the shell is cut at 7.5" tall rather than 3.75". Cut a breast wallet at its closed height and you have a card holder.
Seam Allowance Formula
Cut Size = Finished Size + (2 × Seam Allowance)
| Stitch Type | Seam Allowance | Notes |
|---|---|---|
| Hand-stitched (saddle stitch) | 3–4 mm (⅛") | Minimum for clean stitching line |
| Machine-stitched | 5–6 mm (¼") | Needs more room for presser foot |
| Edge-folded (no stitch) | 8–10 mm (⅜") | For folded-edge card slots |
Leather Thickness Considerations
| Component | Recommended Thickness | Leather Weight |
|---|---|---|
| Outer shell | 1.0–1.2 mm | 2.5–3 oz |
| Card slots | 0.6–0.8 mm | 1.5–2 oz |
| Bill compartment divider | 0.6–0.8 mm | 1.5–2 oz |
| Lining (if used) | 0.4–0.6 mm | 1–1.5 oz |
Worked Example: Bifold Wallet with 6 Card Slots
Saddle stitched, 1.0 mm shell leather. Build the shell width in three steps:
- Open flat: 4.25" × 2 panels = 8.5"
- Fold compensation: π × 1.0 mm = 3.14 mm, which is 0.124"
- Seam allowance: 0.125" on each side, so 0.25"
Outer shell cut size: 8.5 + 0.124 + 0.25 = 8.87" × 3.75". That is the figure the calculator returns for these inputs.
Card slot pieces, 3 per side, overlapping:
- Bottom slot: 4.0" × 2.5" (fully exposed)
- Middle slot: 4.0" × 2.0" (overlaps bottom by 0.75")
- Top slot: 4.0" × 2.0" (overlaps middle by 0.75")
Add 0.125" seam allowance to each piece on three sides (left, right, bottom). Top edge is folded.
Buy a square foot of 2.5–3 oz leather for the shell and a square foot of 1.5–2 oz for the slots and divider. That leaves enough waste margin to recut a slot you nick with the skiving knife, which you will.
Fold Compensation
When leather folds, the outer layer stretches and the inner layer compresses. For each fold, add:
Fold Compensation = π × Leather Thickness × Number of Folds
For a bifold with 1.0 mm leather: π × 1.0 mm × 1 fold = 3.14 mm (~⅛") added to the outer shell length.
For a trifold with 1.0 mm leather: π × 1.0 mm × 2 folds = 6.28 mm (~¼") total.
This small addition prevents the wallet from splaying open when loaded with cards.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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