Fabric Shrinkage Calculator
Measure shrinkage from a test piece before and after washing, then estimate the starting dimensions needed to reach a chosen size after the same treatment.
Method: shrinkage is calculated separately across width and length. A positive percentage means the sample became smaller; a negative percentage means it grew in that direction.
Shrinkage % = (before − after) ÷ before × 100. To estimate a required starting dimension, the desired after-wash size is divided by the sample’s retained proportion: after ÷ before.
Use a representative test
Wash and dry the sample in the same way you intend to treat the finished item. Different fabrics, finishes, temperatures and drying methods can produce different results.
Worked example
A 50 cm sample that finishes 48 cm wide has 4% width shrinkage. If the same sample finishes 47 cm long, length shrinkage is 6%. To finish at 100 × 150 cm after the same treatment, the estimated starting size is about 104.2 × 159.6 cm.
Common question
What if the fabric becomes larger? The calculator shows negative shrinkage as growth and uses that measured retained proportion when estimating the starting size.
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