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Trouser Hem Calculator

Calculate new hem position and fabric needed for trouser length alterations.

Waistband to current hem edge

Waistband to desired hem fold

Half circumference at hem (flat)

Determines hem allowance needed

Amount of fabric pooling at shoe

How We Calculate This

Shortening

Amount to Remove = Current Length - Desired Length

The removed fabric adds to the available hem allowance. Trim to the ideal allowance for your hem type.

Lengthening

The desired extra length is taken from the existing hem allowance. If insufficient, a facing or false hem is needed.

Hem Tape

Tape Length = Leg Width x 2 + 3cm overlap

Frequently Asked Questions

Last updated: March 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.