What shrinkage and pre shrinking mean

Sep 12, 2026

Short answer: Shrinkage is when fabric pulls together after washing. Pre-shrinking is a factory treatment where the fabric shrinks in advance, so most of the shrinkage does not happen at home.

Why fabric shrinks

During knitting and dyeing, fabric is stretched and held under tension. The fibres therefore sit a little longer than they naturally want to. In the first wash, the fibres relax in the warm water and pull back towards their natural length. That is why clothes can end up slightly shorter or narrower after the first wash.

What pre-shrinking does

In pre-shrinking, the fabric is exposed to steam, moisture and heat at the factory before it is cut. Most of the shrinkage then happens before the garment is sewn, and the measurements hold better afterwards. It is common for quality items, but it does not remove all shrinkage. See the items in most popular at Copenhagen Bamboo.

Why a little shrinkage still happens

Even pre-shrunk fabric can pull in slightly in the first wash. Cellulose fibres such as bamboo viscose and cotton absorb water and swell a little, and when they dry again the fabric can end up slightly denser. The difference is usually small, but you notice it most in the length of T-shirts and sleeves.

Heat makes the biggest difference

The hotter the wash and drying, the more the fabric shrinks. The tumble dryer is the biggest culprit, because heat and movement make the fibres pull tightly together. Wash at 40 degrees and let clothes air dry to keep shrinkage to a minimum. This also applies to the most popular for men.

How to wash new clothes the first time

The first wash is the most important. Wash at 30 or 40 degrees on a gentle programme and avoid spinning at the highest speed. Take the clothes out straight away, shake them and ease them into shape while damp. Lay heavy garments flat to dry and hang lighter ones on a hanger.

Sweat and thick fabrics

Thick fabrics such as sweat hold more water and take longer to dry. If they hang on a line, the weight of the water can pull them longer while the width pulls in. Lay sweat flat on a drying rack and smooth it into shape with your hands. See the styles in bamboo sweatshirts for men.

Choose your size with shrinkage in mind

If you are between two sizes, it can help to choose the larger one if you want a little room after washing. This matters most for T-shirts, where length has a big effect on fit. If you always wash gently and air dry, you can usually choose your normal size without worry.

Can shrunken clothes be saved

If a garment has shrunk a little, it can often be stretched partly back. Soak it in lukewarm water, gently pull it into shape while wet and let it dry flat. This works best on knits, because the loops can stretch. The result is rarely as good as new, but it can make a noticeable difference.

Frequently asked questions

How much does bamboo viscose shrink

Typically two to four percent at 40 degrees. Hotter washes and tumble drying cause more shrinkage, so gentle washing and air drying keep the measurements best.

Does the fabric shrink again in the second wash

Very little. Most of the shrinkage happens the first time, after which the fabric keeps its measurements as long as you wash at the same temperature and avoid the dryer.