Yes — for anything you intend to wash. Fabric shrinks on its first wash, and it does not shrink evenly across the grain.
A garment made from unwashed fabric and then laundered comes back smaller, and often distorted rather than just smaller: cotton typically shrinks more along the length than across it, so a fitted bodice becomes short before it becomes tight.
Wash it as you intend to wash the garment. Same temperature, same cycle. There is no point pre-washing at 30 °C if the finished shirt will go through at 60.
Two more reasons that catch people out.
Colour. Deep reds, indigos and some blacks bleed on the first wash. Finding that out on an offcut is better than finding it out on a garment with a white collar.
Finish. Some fabrics are sold with a dressing that makes them feel crisper than they really are. Washing removes it and shows you what you are actually working with — which occasionally changes what you decide to make.
What not to prewash. Dry-clean-only fabric — press it with steam instead to relax it. Anything you are certain will never be washed. And interfacing, which is fused rather than laundered, though you should still pre-wash the fabric you fuse it to.
Questions people actually ask
What about knits?
Prewash, and consider washing twice — jersey often continues to shrink on the second wash. It also relaxes, which changes how it drapes.
My fabric frayed badly in the wash.
Overlock or zigzag the cut ends before washing, or cut with pinking shears. A loose weave can lose several centimetres to fraying otherwise.
Last reviewed 2026-08-11