I am making a hat for my son--very simple little pumpkin hat on double pointed needles for his Halloween costume. I made one for my younger son, but the directions I have are only for a small child. I cannot find one for an adult size head. My oldest son is 4 years old and has a rather large head (21"). I'm making the hat out of an orange bulky-weight yarn on 10 1/2 needles and getting a gauge of 4 stitches per inch. My question: Is there a rule-of-thumb for how big to make a hat based on the stretch factor? In other words, I don't think I would necessarily want to make his hat 21" but a bit smaller to allow for the stretch. If this is correct, is there a general rule-of-thumb for this or a percentage of stretch I should allow for? I realize that K2, P2 ribbing is much stretchier than stocking stitch. The hat I'm making is just a roll brim in stocking stitch, though. How does one go about factoring in the stretch when planning a pattern? I would love to make more of these hats and not feel tethered to a set of instructions every time. I hope I've worded this properly. Any assistance would be greatly appreciated!
thanks
karlisa