Understanding Fabric Shrinkage Rates
By The Velocity Wear Team
A shrinkage rate describes how much a fabric is expected to lose in washing and drying, and it is normally stated separately for length and for width because the two are rarely the same. Most of it happens in the first wash, when the tension built into the knit relaxes. What follows after that is largely down to how the garment is dried.
Two Different Things Are Called Shrinkage
The first is relaxation shrinkage. Knitting and finishing pull yarn into a slightly stretched state and hold it there, and washing releases it. This is the big one, it happens mostly on the first wash, and it is not a defect. The second is progressive shrinkage, which continues over repeated cycles. That is a much smaller effect on cotton jersey and a much larger one on wool, where the scales on the fibre interlock under heat and agitation and the fabric felts. Confusing the two is why people expect a cotton tee to keep shrinking forever when it will not.
Why Length and Width Behave Differently
Knitted fabric is a structure of interlocking loops, and those loops are not symmetrical. Tension applied during knitting and finishing tends to be greater along the length of the roll, so that is the direction with more stored strain and more to give back. In practice this is why the classic complaint about a washed cotton tee is that it has become short and boxy rather than tight across the chest. The body length goes first. Knowing that changes what you check when a sample comes back.
What Pre-Shrunk Actually Means
Pre-shrinking, sometimes described as compacting or sanforising, mechanically relaxes the fabric before the garment is cut, so most of the relaxation shrinkage has already been spent. It reduces movement significantly. It does not eliminate it, and the term is not a guarantee of a specific figure. In general, better-constructed knits from combed or ring-spun yarn tend to be more dimensionally stable than cheap open-end jersey, which is one of the less obvious reasons a heavier, better blank holds its shape over a uniform programme.
- Cotton: the most movement of the common fibres, and the reason most shrinkage conversations happen at all.
- Polyester: very stable dimensionally, since the fibre is set with heat during manufacture and washing does not undo that.
- Poly-cotton blends: broadly proportional, so the more polyester in the mix the less the garment moves.
- Viscose and rayon: can move a great deal and are more sensitive to washing than their handle suggests.
- Wool: prone to felting shrinkage that continues with heat and agitation, which is a different mechanism entirely.
Your Garment Has Already Been Heated Before You See It
This one surprises people. A screen-printed garment goes through a cure tunnel, and a heat-pressed one spends time under a hot platen. That is real heat applied to the fabric before it ever reaches a washing machine, and it releases some of the stored tension in the process. It is one reason a printed garment can move slightly less in its first wash than an identical blank from the same box. It is not a large effect and it is not a substitute for pre-shrunk fabric, but it explains a discrepancy people occasionally notice and cannot account for.
Shrinkage and the Print Sitting on Top of It
The print does not shrink. The fabric under it does. On a small chest logo nobody notices. On a large front or back print on cotton jersey, the fabric can draw in slightly around and beneath a film that has no intention of following, and the result is a print that looks subtly rippled or bowed rather than flat. This is also why some people believe their print shrank. It did not. It stayed the same size while the garment around it got smaller, which reads as the print growing relative to the body.
Ordering With Shrinkage in Mind
Two practical points. First, ask whether a size chart is quoted pre-wash or post-wash, because the two describe different garments and comparing across suppliers without knowing which is a good way to get a surprise. Second, do not size up hoping to end up with a longer body after washing, because you will get a wider garment that is still short. Body length and width do not shrink in the same proportion, so a size up changes both and fixes neither.
For uniform programmes there is a third point worth writing down: consistency across reorders matters more than the absolute figure. If your team's first batch settled to a particular fit, staying with the same blank on the reorder keeps the new starters looking like everyone else.
“"Cotton does not so much shrink as remember. The first hot wash simply lets it go back to the shape it was knitted in."”
How to Slow It Down
Cool washing and line drying handle most of it, since heat is what releases stored tension and the tumble dryer supplies more heat and more agitation than anything else in the process. Beyond that, choose the fabric for the outcome: if dimensional stability genuinely matters, a poly-cotton blend or a well-made pre-shrunk cotton is a more reliable answer than any washing habit. Point wearers at the garment's own care label, since blends and technical fabrics vary.
Velocity Wear supplies custom apparel online from a 20-piece minimum, with sizes mixed freely within the run rather than 20 per size, so you can spread a team across a full size range in one order. Bulk discounts reach up to around 40% as quantities rise, and UK delivery is typically 2 to 5 working days after dispatch on a tracked service.