So I’m going to make the Hot Head hat from SnB for my bro. The largest size in the pattern makes a hat with a circumference of 22". My bro wears a size 8 hat which corresponds to 25" The pattern is a simple K2,P2 rib. So, do you think there’ll be enough stretch in a 22" circumference hat for a 25" head? Or do I need to alter the pattern (and um, how would I do that :??)
It ought to stretch enough, but you could go up a needle size and that should do it.
If the hat is mostly ribbing then you should have no problems. Ribbing stretches quite a lot. If you are still concerned about it, then do what PP said and go up a needle size.