Angie,

Welcome!

The size depends on which craft you're doing and other factors.

If you're working in cross stitch, it depends on the size of your fabric.

If you're working in crochet or knitting, that depends on your gauge. For that, you must make a swatch to determine how many stitches and rows you're getting per inch. That's something no one can determine but you. Everyone's swatch will be different, depending on your needle or hook size, the fiber you'll be using and how tight or loose your tension is.

This is why we can't give a blanket answer and the reason there's no information in the pattern about that, because it's different from person to person, with everyone's guages being so unique.