I don't pre-wash my fabric because I buy in such large quality so I don't know who much it will shrink. Be careful to buy RK Kona cotton from a quilt store and NOT a chain store. You will be getting 2nd quality fabric if you do that. RK sells the fabric that is NOT good enough for quilt stores selling it to jobbers who then sell it to the chain stores. If it is NOT on an official RK label at the end of the bolt, it is 2nd quality fabric.