Fabric shrinkage is one of the leading causes of fit failures and buyer rejections in Bangladesh's garment exports. A garment that measures perfectly before washing may be 3–8% smaller after the first wash — and if the pattern maker did not account for this, every piece in the order will be out of spec. This guide explains how to measure shrinkage correctly and build it into your production process.
How to Measure Shrinkage
Shrinkage is measured on a fabric sample of known dimensions, washed and dried under the same conditions as the garment will be processed in production. The standard method uses a 50cm × 50cm sample with marks placed 40cm apart in both warp (length) and weft (width) directions.
Shrinkage % = [(Original measurement − After-wash measurement) / Original measurement] × 100 Example: Warp (length) before wash: 40 cm Warp after wash: 38.2 cm Warp shrinkage = [(40 − 38.2) / 40] × 100 = 4.5% Weft (width) before wash: 40 cm Weft after wash: 39.1 cm Weft shrinkage = [(40 − 39.1) / 40] × 100 = 2.25%
Typical Shrinkage Ranges by Fabric Type
Different fabric constructions and fibres have very different shrinkage behaviours. Understanding typical ranges helps you flag when a shrinkage test result seems unusual — and when to send the fabric back for a pre-shrinking treatment.
Typical Shrinkage Ranges After First Wash
| Fabric Type | Warp Shrinkage | Weft Shrinkage | Notes |
|---|---|---|---|
| 100% Cotton single jersey | 4 – 8% | 2 – 5% | Higher in length than width |
| Cotton/polyester blended jersey | 2 – 5% | 1 – 3% | Polyester reduces shrinkage |
| 100% Cotton poplin / woven | 2 – 5% | 1 – 3% | Lower than knit |
| Denim (unwashed) | 3 – 7% | 1 – 4% | Sanforized denim should be ≤1% |
| Fleece / heavy jersey | 5 – 10% | 2 – 6% | High shrinkage — always pre-shrink |
| Viscose / rayon | 5 – 12% | 3 – 8% | High moisture absorption = high shrinkage |
How to Allow for Shrinkage in Patterns
Once you know the shrinkage percentage, you add the shrinkage allowance to the pattern dimensions before cutting. The formula is straightforward but important to apply in the correct direction.
Pattern dimension with shrinkage allowance = Finished measurement / (1 − Shrinkage %/100) Example: Finished body length = 70 cm, warp shrinkage = 5% Pattern length = 70 / (1 − 0.05) = 70 / 0.95 = 73.68 cm ≈ 73.7 cm (Not 70 × 1.05 = 73.5 cm — this common shortcut understates the allowance by 0.2 cm)
Tip
Always wash your shrinkage test sample using the exact wash program that will be used in production — water temperature, machine type, detergent concentration, drying method. A sample tested at 30°C when production washes at 60°C will give you completely wrong numbers.