Fabric shrinkage: what to expect, and how to spec it so it is not a surprise
Cotton fabric changes dimension twice after it is woven: once through wet processing (scour, bleach, dye) and again in the end user's first wash. If you do not spec a limit, you inherit whatever the mill's default is.
Typical movement
- Greige to finished: roughly 3–8% in the width and 2–5% in the length, depending on how tightly the cloth was woven and sized.
- Residual shrinkage (finished cloth, first wash): 5–10% for an untreated cotton; 1–3% for a sanforised (compressive-shrunk) cotton.
Tighter constructions and heavier cloths move less. Loose, open weaves and low-twist yarns move more.
What sanforising does
Sanforising runs the damp cloth through a rubber belt that compresses it lengthwise, then dries it in that state — forcing most of the shrinkage out before it is sold. A sanforised cloth is quoted with a residual shrinkage figure, and that is the number your cut-and-sew planning should use. Workwear, uniforms and bedding are almost always specified sanforised; raw and one-wash denim deliberately are not.
How to spec it
- State a maximum residual shrinkage — e.g. "≤3% warp and weft after one 40°C wash, tested to ISO 6330 / ISO 5077."
- Say whether you want it sanforised or will allow for the movement in your pattern.
- Ask for a test report against that figure with the bulk, not just a verbal assurance.
- For a target finished width, tell us — we quote the greige width needed to land it after shrinkage.
We build the preparation and any sanforising into the quoted lead time, and confirm the shrinkage figure on a sample before bulk.