Any yarn any needle answer stitches to cast on chart
by Linda McMurtrie
(Salem Oregon USA)
It doesn't really matter what size your yarn is, what matters is getting a nice dense square that is the right size.
Once you have knitted a swatch, have your gauge and like the thickness of it, then use this helper:
Stitches per inch # of stitches to cast on
3 24
3.5 28
4 32
4.5 36
5 40
6 48
If your swatch is too light weight, go to a smaller needle. I recommend using one needle size smaller than the recommended needle size on the yarn packaging to make it a little warmer.