quality · 5 min read

Fabric shrinkage: what causes it and how to control it

Shrinkage is not one number. It depends on the fibre, the construction and the finishing, and it changes with the number of washes you test. Ask for the method, not just the percentage.

By Weft Bridge · Reviewed by our Guangzhou sourcing team · Updated 2026-11

Three mechanisms

Relaxation: tension from weaving or knitting is released in the first wash. Most of it happens once.
Swelling: cellulose fibres absorb water and expand, then contract on drying. Cotton and viscose are affected; polyester much less.
Felting: wool fibres lock together under heat and agitation. Irreversible.

Typical numbers

Fabric	Warp / length	Weft / width
Cotton woven, sanforized	1–3%	1–3%
Cotton woven, unfinished	3–6%	3–5%
Cotton jersey	5–8%	3–6%
Linen, unwashed	5–10%	3–6%
Viscose woven	5–8%	4–6%
Polyester woven	0–2%	0–2%

What to write in the PO

The test method (AATCC 135 or ISO 6330) and the number of wash cycles.
The maximum shrinkage after three cycles, length and width separately.
Whether the fabric is pre-shrunk, and by which process.
The remedy if the bulk exceeds the tolerance.

FAQ

Why does my sample shrink more than the bulk?

The sample may not have had the same finishing, or it was cut from a different position in the loom. Test a piece from the bulk.

Does washing temperature matter?

A lot. Test at the temperature and cycle you will put on the care label, not at 30 degrees if the label says 60.