An easy way to find your row gauge is to knit a few rows, knit a row in a contrast color, set your row counter back to zero, knit 50 rows, knit another contrast row , then a few more rows before taking it off of the machine. You have to let machine knitting “rest” a while (even overnight) before you measure it. Depending upon your project, you might even want to launder the piece before measuring. Now measure the knitting between the contrast rows. You will know how many rows are between the two contrast rows. The rest is a matter of doing a little math to determine how many rows you need to get the right length. Your swatch can be frogged and the yarn used in your project if you are concerned about running out of yarn.