I cast on 72 sts for an average adult hat. I did bump the needle size down to 9 for the smallest needle size and 10.5 for the body of the hat. This pattern is very easy to modify with a chart. I added a 9 row “xo” chart after knitting 4 rows of the body and still had enough space to decrease the crown as written. Added additional 1.5” ribbing so brim can be rolled up. I would use this yarn again if someone has a lanolin allergy. It knit up soft and stretchy-perfect for good fitting hats.