Skip to content
DG KalkulátorCalculate. Understand. Decide.
HomeHome & DIY
Home & DIY

Fabric shrinkage and cutting allowance calculator

Calculate the width and length changes, and the cutting size required for the desired finished size, from the pre- and post-wash test measurements.

Free & no registration Calculated in your browser
01

Your inputs

The starting values are an example.

The calculation also back-calculates this to the pre-wash size.

Decimals: 12.5 · Thousands: 1,234.56. Follow the field instructions for lists.

02

Your result

Enter your values and select Calculate.

Your calculation will appear here.

Your result will include the relevant values and units.

Understand the calculation

Formula and example

How it is calculated

cutting size = (finished size + 2 × finished seam allowance) / (after test / before test)

Worked example

From 20 cm to 19 cm: 5% shrinkage; for a 50 cm finished size with no allowance, 52.6316 cm is required.

Things to check

  • The test is only valid under identical washing, drying, ironing, and grain direction conditions. Multiple wash cycles may cause different changes.
  • Pre-shrinking the entire fabric and re-measuring before cutting is generally safer. The specified allowance per side refers to the post-wash state; the calculator also rescales this.

Frequently asked questions

Is it enough to cut 5% larger for 5% shrinkage?

Not exactly: the required starting size is divided by 0.95. For a 100 cm final size, this means 105.2632 cm is required, and this is only true if the test is reproducible.

Why do we measure the two directions separately?

Fabric may change differently lengthwise and crosswise. To calculate area change, we multiply the two retention ratios. Negative shrinkage means stretching.