How much does cotton shrink?

Untreated 100% cotton typically shrinks 3-5% in length and 2-3% in width on the first wash in warm water. Pre-shrunk cotton shrinks less (1-2%). Tumble drying increases shrinkage further. Always pre-wash cotton before cutting your project.

Does washing temperature affect shrinkage?

Yes, hotter water causes more shrinkage. Cold water (30°C) causes about 30% less shrinkage than warm water (40°C). Hot water (60°C) causes about 40% more shrinkage. The first wash causes the most shrinkage; subsequent washes cause minimal further change.

Should I tumble dry fabric before cutting?

If you plan to tumble dry the finished garment, yes. Tumble drying typically adds 20-30% extra shrinkage on top of the wash shrinkage. If you will always hang dry the finished item, pre-wash without tumble drying.

Does fabric shrink more in length or width?

Fabric typically shrinks more along the length (warp direction) than the width (weft direction). Length shrinkage is usually 1.5-2x the width shrinkage. This is because lengthwise yarns are under more tension during weaving.

SewCalcs

Fabric Shrinkage by Fiber Calculator — Pre-Wash Prediction

Predict fabric shrinkage by fiber content and calculate pre-cut allowances.

Fiber Type

Washing Method

Enter the washing method

Fabric Length (before wash)

Length measurement

Fabric Width (before wash)

Width measurement

How We Calculate This

This calculator estimates shrinkage based on fiber type, washing temperature, and drying method, then shows the expected finished dimensions and how much extra to cut.

The formula

Shrinkage % = Base fiber shrinkage × Wash temperature factor × Tumble dry factor

Shrunken size = Original size × (1 - Shrinkage %)

Pre-cut allowance = Original size - Shrunken size

Frequently Asked Questions

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Last updated: March 2026

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