Fabric shrinkage of 3% is acceptable for many woven shirting and home fabrics, but not for all. Typical limits are around 3 to 5% for woven cotton, tighter for fitted garments and looser for some denim. The limit has to be written into the order, along with the test method, before you buy.
A shrinkage test measures how much a fabric changes size after a controlled wash and dry. It is one of the cheapest tests you can run, and one of the most common causes of complaints when it is skipped.
How does a fabric shrinkage test work?
The lab marks a measured square on a sample, usually with three marked lengths in each direction. It then washes and dries the sample under set conditions, lets it relax, and measures again. The change is shown as a percentage in the length direction (warp or wale) and the width direction (weft or course).
A minus sign means the fabric got smaller. A plus sign means it grew. Both can be a problem, and both are reported by direction.
The test methods most used for export are ISO 6330 for the washing and drying procedure and ISO 5077 for measuring dimensional change. AATCC 135 is common for US buyers. The methods differ in wash temperature, cycle, drying and the way the sample is conditioned. A result under one method cannot be compared directly with a result under another.
What is a reasonable limit?
There is no single legal figure. The buyer sets the limit. These are the usual starting points, to be adjusted for your product and your customer:
- Woven cotton shirting and bottoms are often limited to about 3% in length and 3% in width after one wash.
- Knits are less stable and many buyers allow a wider range, with separate limits for length and width.
- Denim is treated differently, because it is often sold unwashed. See what shrinkage is acceptable for denim.
- Bedding and towels have their own norms, set out in home textile shrinkage limits.
Why 3% is not the whole answer
A fabric that shrinks 3% in length and 3% in width is a different problem from one that shrinks 1% in one direction and 5% in the other. The second distorts the garment, causes twisting and spoils the fit, even though the average looks fine. Always state both directions and set the limit for each.
The number of washes also matters. A limit after one wash tells you nothing about what happens after five. If your customer will wash the product many times, ask the lab for a repeated-wash test.
Finally, the fabric state matters. Fabric that has not been pre-shrunk, or compressively finished, will keep shrinking. Ask the mill whether the fabric has been through a mechanical shrinking process, and test the finished fabric, not the greige.
How to put it in your order
Write the limit into your specification in one line: the maximum shrinkage in each direction, the test method and the number of washes. Also say whether the result applies to every roll or to the average of the lot. The format is in how to write a fabric specification.
Ask for a test report from an accredited lab on a production-lot sample, not on the earlier approval sample. Run your own test too, on fabric drawn from the finished lot, because the mill's laboratory is not independent.
Next step
We have lots tested at independent labs before they ship, and we can set the shrinkage method and limits with you so that the report means the same thing at both ends. Book a free sourcing review if you want that built into your next order.