Shrinkage Rate

Shrinkage rate measures the percentage by which fabric contracts in length and width after washing, drying, or other processing. This specification is essential for product development and quality control, as excessive shrinkage can render finished products unusable or require oversizing during manufacturing to compensate.

Testing follows a standardized procedure. Mark precise dimensions on the fabric before washing, launder according to the ISO 6330 standard (which specifies water temperature, agitation, and detergent), dry according to the specified method, then measure the dimensions again. The shrinkage rate is calculated as: ((Original dimension − Final dimension) ÷ Original dimension) × 100%. Warp and weft directions are measured separately, as shrinkage often differs between them.

Multiple factors influence shrinkage behavior. Natural fibers generally shrink more than synthetics because their structure absorbs water and releases tension introduced during weaving. Yarn twist affects shrinkage—higher twist creates more stored tension that releases during washing. Fabric construction plays a role, with tighter weaves typically showing less shrinkage. Finishing treatments can dramatically reduce shrinkage; sanforizing, a mechanical pre-shrinking process, brings cotton shrinkage below 1%. Washing conditions matter too—hot water and aggressive agitation increase shrinkage compared to gentle cold washing.

Industry standards typically require shrinkage below 3% for bedding and apparel, with premium products held to below 1%. When specifying fabric width, buyers should account for expected shrinkage during finishing to ensure the final product meets dimensional requirements. For fabrics sold by weight (GSM), note that shrinkage increases GSM since the same mass occupies a smaller area after shrinking.