What some of us less talented members use is a Wonder Knitter. It is a modern version of what used to be called knitting nancies. I use a class 6 wool, very heavy. Instead of measuring, I count stitches, 375 for a large set and 325 for small. A large pair of ties will fit a 16" to 19" calf, the small works for 13" to 15". Once you've tried a few, adjust as needed.