Illustrative situation
A brand’s first lot of T-shirts shrank very little in the wash, but the reorder shrank noticeably and fits shorter. Both lots were from the same style, and the factory says both pass its tests.
Main answer
Shrinkage differs between batches when the fabric lot, the amount of relaxation, the finishing or the way it is tested changes, so a style that passed once is not guaranteed to pass again. Fix the test method and the shrinkage limit in writing, and test each bulk fabric lot before cutting instead of relying on an earlier result.
Why lots differ
Knitted fabric is stretched in knitting and finishing and then recovers when it is washed, so how much it was relaxed before cutting changes how much it moves later. A different yarn lot, a change in finishing temperature or dwell time, or a different dye house can all alter shrinkage. A reorder often uses new fabric even when the specification is the same.
Two lots, two tests
Differences in the test method also create apparent differences. ISO 5077 covers the determination of dimensional change in washing and drying, and AATCC TM135 covers dimensional changes of fabrics after home laundering. They use different procedures, machines and drying options, so results from one cannot be compared with the other. A report that does not state the method, washing temperature and drying type is not comparable.
What to write down
State the method, such as the standard and edition, the washing programme and temperature, the drying method, the number of cycles and the measured directions, length and width. Set the limit as a percentage for each direction and say whether it applies to fabric or finished garments. Say what happens if a lot exceeds it.
What to test and when
Ask for a fabric test on each bulk lot before cutting, and a garment test on a sample from the first finished pieces. Compare with the approved reference. If a lot is out of tolerance, the factory can adjust pattern allowances, re-finish the fabric or replace it. See product options on T-shirts and seamless T-shirts and polos.
Fact, recommendation, uncertainty
- Established fact
- ISO 5077 and AATCC TM135 both measure dimensional change after washing, but use different procedures, so results are not interchangeable.
- Recommendation
- Fix the test method, cycles and limit in writing and test every bulk fabric lot before cutting.
- Uncertainty
- A laboratory shrinkage figure does not predict exactly how a garment will change in each customer’s machine.
Sources and further reading
- ISO 5077:2007 — Determination of dimensional change in washing and drying
- AATCC TM135 — Dimensional Changes of Fabrics after Home Laundering
Sources checked on 24 October 2026. Standards bodies sell the full texts; we cite what their public pages state. General information, not legal or technical certification advice.
More perspectives from the team
Three further views on the same question, each by function. They add conditions and limits to the main answer; they are editorial notes, not customer reviews.
Sino Finetex Editorial Team Sourcing
Ask each supplier to state the method behind its shrinkage figure, and compare only like with like. Limit: a low figure from a gentle method may not reflect your market’s washing. Ask whether the reorder will use the same fabric lot and finishing line as the approved one.
Sino Finetex Editorial Team Product selection
Allow for expected shrinkage in the pattern so the garment sits at the target size after washing. Limit: a very high allowance means the unwashed garment looks oversize. Keep a note of the approved lot’s shrinkage so you can see when a reorder drifts.
Sino Finetex Editorial Team Quality & care
Measure garments before and after washing at the same points and record both. Limit: measuring points must be identical or the figure is meaningless. Retain an unwashed piece from each lot so you can test it later if a complaint arrives.
Related products
- Seamless T-Shirts & Polo Shirts Manufacturer
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- T-Shirt Manufacturer
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- Products
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