I just finished a beanie that turned out too big - it said it was for a 22-23" circumference head - well it’s about an inch too big - I originally cast on 96 sts - how many sts should I cast on if I want to remake the beanie 1 inch smaller?
The number you cast on has more to do with the weight of yarn and needles you are using. For a standard hat made with worsted weight yarn and size 7-8 needles you’d cast on about 80 stitches. That’s what I use for the hats I’ve made. If there is a pattern involved you need to decrease accordingly so the pattern will come out right.
Measure the head, then subtract a couple inches and multiply that times your sts/inch. If you’re getting 4½ sts/inch and need to fit a 23" head, you’d need between 90 and 95 sts (20 to 22"). If you have to adjust the st number to an even number or one divisible by 4 or 6 or whatever, go down.