How to shrink (or stop shrinking) a BJJ gi

What actually causes shrinkage

Cotton contracts with heat and agitation. The two biggest levers are wash temperature and drying method: hot wash plus a hot tumble-dry shrinks the most, while cold wash and hang-dry shrinks the least. Fabric matters too — pre-shrunk and ripstop materials move far less than standard cotton pearl weave.

If your gi is slightly too big

You can intentionally shrink a roomy gi by washing warm-to-hot and tumble-drying on medium. Go gradually: wash and dry once, check the fit, repeat only if needed. You can shrink a gi down, but you can't grow it back, so sneak up on the size rather than blasting it on the hottest setting once.

If your gi already fits

To keep a gi exactly where it is, wash cold and hang-dry. This also extends the life of the fabric and the colour. Heat is the enemy of a gi that already fits — keep it out of the dryer.

Estimate before you wash

Because real shrinkage depends on your specific gi, prior washes and exact blend, treat any estimate as a direction rather than a precise figure. The gi shrinkage calculator takes your fabric, wash temperature and drying method and tells you which way — and roughly how much — your gi is likely to move.