Fabric Shrinkage Calculator

Test a swatch first, then find out how much extra to cut so your finished piece is the right size after its first wash.

Step 1: Test a swatch

Swatch measurement before washing (in)

Same swatch after washing/drying (in)

Step 2: Cut size for a finished measurement

Shrinkage % (from Step 1, or your own)

Desired finished measurement (in)

Why a test swatch beats a guess

Shrinkage varies enormously by fiber and weave — some quilting cottons barely shrink at all, while some linens and non-preshrunk wovens can shrink 5% or more. Cut a swatch (at least 10" square works well for accuracy), measure it, wash and dry it exactly the way you plan to launder the finished piece, then measure again.

The formulas

Shrinkage % = (before − after) ÷ before × 100. To reverse it: cut size = desired finished size ÷ (1 − shrinkage% ÷ 100). If a fabric shrinks 4% and you want a 40" finished piece, you need to cut it at roughly 41.7" before washing.

Pre-wash instead, when you can

For garment-weight fabric, it's often simpler to wash and dry the yardage before cutting at all, so the finished cut pieces are already the size you want with no math needed. This calculator is most useful for quilting cotton and other fabrics people prefer to keep unwashed until after piecing.