Hem Allowance and Fabric Calculator
Calculate the correct hem allowance for different hem types, how much extra fabric to buy for hemming, and the finished length of your garment.
Hem Allowance by Hem Type A double-fold narrow hem (shirts, light garments): 5/8" total (two folds of 5/16"). A double-fold wide hem (skirts, trousers): 1.5" to 2" total. A blind hem on trousers: 1.5" to 2". A rolled hem (chiffon, sheers): 1/4" or less. A horsehair braid hem (ball gowns): 1" to 1.5".
Why Hem Width Matters A wider hem hangs better and adds weight to the bottom of a garment. For curved hems (A-line skirts, flared trousers), narrow hems are easier to ease around the curve. For straight hems, wider is usually better.
Fabric Shrinkage Always pre-wash and dry fabric before cutting. Most cotton shrinks 3-5%, linen 3-6%. If you cannot pre-wash, add 5-10% extra length to your fabric purchase as insurance.
Cutting Length Formula Cut length = Finished length + Hem allowance + Seam allowance at waist/top