Most yarns that I buy, and patterns that I have laying around, give the gauge in the number of stitches and rows that equal 4 inches. Then when I do a 4x4 inch swatch square, and pull out my measure, I actually measure in the center of my swatch a 1x1 inch square, and do the math.
So if your pattern were to say 6 stitches and 6 rows = 1 inch, and the yarn you were buying gave the measure in a 4x4 square, you would be looking for yarn that stated 24 stitches and 24 rows = 4 inches.
If your pattern said 20 stitches and 24 rows = 4 inches, and your yarn gave the measure in stitches/rows for 1 inch, then you would be looking for yarn that said it was 5 stitches and 6 rows for 1 inch.
Like I mentioned, usually my patterns and my yarn both reflect gauge as stitches and rows per 4 inches.
The important thing is, what is your stitch and row gauge when you make a swatch.