Hobbs Heirloom wool shrinks about the same amount as most cotton battings -- about 3%. I agree with Mitty that you could dampen the batting and dry it in the dryer to preshrink a little. Just make sure it is a dryer big enough to allow the batting to tumble. Packing it into a small domestic dryer would be bad. I got burn marks on a comforter I stuffed into our home dryer, so learned that the hard way.