Hemming Calculator
Calculate hem allowance and fabric to cut when shortening pants, skirts, and dresses.
Covers blind hem, double-fold, and rolled hems with seam allowance.
Hemming allowance is the extra fabric folded under (and usually sewn) to create a clean, finished edge on garments. The correct allowance depends on the fabric type, hem style, and garment use.
Hem Allowance Formula:
Cut Length = Finished Length + Hem Allowance + Seam Allowance (if applicable)
Standard hem allowances by garment type:
| Garment / Style | Allowance |
|---|---|
| Dress trousers (machine hem) | 1.5–2 inches |
| Jeans (serged raw hem) | 1 inch |
| Casual pants (blind stitch) | 1.5 inches |
| Dress / skirt (narrow hem) | 0.5–1 inch |
| Dress / skirt (wide hem) | 2–3 inches |
| Jacket / blazer sleeve | 1.5 inches |
| Shirt bottom (rolled hem) | 0.25–0.5 inch |
| Curtains / drapes | 3–4 inches |
| Stretch fabric (knit) | 0.75–1 inch |
Double-fold hem (most common for clean finish): For a 1-inch finished hem, cut with 2-inch allowance — first fold is 1 inch, second fold is 1 inch, hiding the raw edge inside.
Worked example — hemming trousers: Client inseam needed: 30 inches Current inseam: 34 inches Amount to remove: 34 − 30 = 4 inches Allowance needed: 1.5 inches Cut at: 30 + 1.5 = 31.5 inches from waistband seam The extra 2.5 inches is trimmed away.
Fabric-specific tips:
- Heavy denim: use a denim needle and reduce allowance to 1 inch — too much bulk at the fold will be visible
- Chiffon / silk: use a narrow rolled hem (0.25 inch) — heavier hems weigh down light fabric and cause distortion
- Knit fabrics: use a twin needle or coverstitch to allow stretch in the hem without breaking thread
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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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