What pre shrunk fabric is

Short answer: Pre-shrunk means the fabric was washed or steamed before it was sewn. Most of the shrinkage has already happened before the item reached the shop, so the garment keeps its measurements better when you wash it at home.

Shrinkage is taken at the factory

When a knitted fabric is made, the fibres are stretched and held under tension. When the fabric later meets heat and moisture, the fibres pull back together. In pre-shrinking, the fabric is treated with heat and moisture in advance, so the fibres contract before cutting and sewing, see bamboo underwear for women.

Why the size holds after the first wash

A pre-shrunk fabric changes only one or two percent in the first wash, if you follow the care label. A T-shirt or pair of briefs keeps almost the same length and width after washing as when you bought it. The size you choose in the shop is still your size after the wash.

Not the same as shrink-proof

Pre-shrunk does not mean the fabric can never shrink. Wash at 60 degrees or tumble dry hot, and even a pre-shrunk fabric shrinks, because the heat pulls the fibres together again. Pre-shrinking covers the shrinkage from normal use, not the shrinkage from too much heat, see bamboo socks.

Why it matters for the fit

Clothes that shrink do not only get shorter. They can also twist, because the fabric does not always shrink equally in every direction. Seams can start to turn, and a T-shirt can end up with a side seam drifting to the front. With pre-shrunk fabric that risk is much smaller, and the fit stays stable.

Length and sleeves

Length is what you notice most when clothes shrink. A long-sleeved garment that loses a few centimetres suddenly has sleeves ending above the wrist. That is why pre-shrinking matters most for long sleeves and long legs. Even a small change decides whether the garment fits right, see long-sleeved styles.

How to wash pre-shrunk clothing

Follow the temperature on the label, and wash a little too cold rather than too warm. Turn the garment inside out and use a mild detergent. The biggest risk is the tumble dryer, because warm air and long movement pull the fibres together. Let the clothes dry on a rack, so they keep their shape.

If the garment has shrunk anyway

If a garment has shrunk a little after a hot wash, you can often stretch it back slightly while it is damp. Pull gently along the length and let it dry flat. It rarely brings back the full size, but it can help. Next time, choose a lower programme and skip the tumble dryer.

When you choose a size

With pre-shrunk fabric, choose the size that fits you today. There is no need to size up to be safe, because the measurements hold when you wash correctly. If you choose too large, the garment fits loosely from the start and stays that way, so it never sits as intended.

Frequently asked questions

What does pre-shrunk mean

That the fabric was treated with heat and moisture before sewing, so most of the shrinkage has already happened before the garment reaches the shop.

Does pre-shrunk fabric not shrink at all

It does, a little. Typically one to two percent in the first wash, if you follow the care label. With too much heat it can shrink more.

Should you buy a size up to be safe

No, not with pre-shrunk fabric. If you wash correctly, the measurements hold, and a size up will simply be too large from the very first day.