quality · 4 min read

Fabric tolerances: how much variation is normal

Every fabric specification is a range, not a number. The argument starts when the range was never agreed.

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

The usual ranges

Property	Typical tolerance	How to measure
Weight, woven	±3–5%	100 cm² sample, calibrated scale
Weight, knit	±5%	Same, after relaxation
Width	±2 cm, or -0 / +2	Selvedge to selvedge, three points
Roll length	±0.5–1%	Measure or trust the meter counter
Shade	Grey scale 4–5	Against the approved dip, D65

Why knit tolerates more

Knitted fabric relaxes after production, so the weight and width settle over days. A knit measured immediately after finishing will read differently a week later.

That is why knit tolerances are wider, and why the measurement method and the relaxation time should be in the specification.

What to write

The tolerance for each property, not just the target.
The measurement method, including sample size and relaxation.
Whether weight is greige or finished.
The consequence of exceeding the tolerance: rejection, credit, or renegotiation.

FAQ

Is ±5% on weight acceptable?

For knits, usually. For wovens, ask for ±3% and check the first roll.

How do I measure GSM?

Cut a known area, weigh it on a calibrated scale, and convert. A 10 cm × 10 cm sample is 0.01 m², so grams × 100 gives gsm.