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