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

Cut a swatch (10in square works well) and measure one side before you wash it.
Wash and dry the swatch the way you plan to launder the finished piece, then measure the same side again.

Step 2: Cut size for a finished measurement

Auto-filled from Step 1 above, or type in a shrinkage percentage from the fabric's own label.
The size you want the piece to be after it's washed, not the size you're about to cut.

Protecting Your Machine on the Go

A padded sewing machine carrying case keeps your machine protected for classes, guild meetings, or trips to the shop for servicing.

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.