Sewing & crafts
Fabric shrinkage calculator
Measure shrinkage in each direction and allow for it before cutting.
A clear answer. Here’s how.
Length retention = after ÷ before, independently for each direction. Shrinkage is (1 − retention) × 100; negative shrinkage means growth. Required prewash size = finished size ÷ retention. Assumes the tested washing, drying and fabric behaviour scale uniformly; add sewing allowances separately.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Sample length before washing (cm)
- 20
- Sample length after washing (cm)
- 19
- Sample width before washing (cm)
- 20
- Sample width after washing (cm)
- 19.5
- Required finished length (cm)
- 100
- Required finished width (cm)
- 80
Example result
- Length shrinkage
- 5%
- Width shrinkage
- 2.5%
- Area shrinkage
- 7.375%
- Required prewash length
- 105.263157895 cm
- Required prewash width
- 82.0512820513 cm