Convert Metric Stitch Length to Stitches Per Inch
I have several sewing machines and if you’re a quilter, maybe you do, too. When it comes to stitch length, some machines use a metric length such as 2.5 or 3.0. This tells you that each stitch is 2.5 or 3.0 millimeters long.
Other machines use an English stitches-per-inch setting such as 12 or 15 or 20. This tells you that in every inch of a seam, there are that many stitches. Setting stitch length to 15 means there will be 15 stitches in every inch.
This post is to explain how you can convert from metric stitch length to stitches-per-inch, or visa versa.
There are 25.4 millimeters in one inch. This is the formula:
25.4 divided by the metric length of the stitch equals the number of stitches per inch.
For example, to determine how many stitches per inch a 2.5 metric setting will give you, do this:
25.4 divided by 2.5 = 10.16 stitches per inch. Round down and use 10 as your setting.
To figure it the other way, in case you need to sew 12 stitches per inch and want to know the metric setting, do this:
25.4 divided by 12 = 2.11, round down to 2.0.
If you needed to sew 15 stitches per inch, 25.4 divided by 15 = 1.69, round up to 1.7 for the metric setting.