Knitting 30 stitches how many inches is it?

Answer 1

I think your question is: if you knitted 30 stitches, how long, in inches, would that be?

There is no way to tell. Different types of yarn (wool, cotton, silk, rayon), stitch up differently. The size of the yarn--fingering, worsted, bulky--would change the length that 30 knit stitches would make. Also the size of the needle would change how long 30 stitches would be.

If you really want to know, knit a swatch of 30 stitches, and measure it yourself. That is the only way to know for sure.