Thread Consumption Equations by Stitch Type

Thread is a small line on a cost sheet that adds up fast across a bulk order, and under-ordering it stops a production line. Thread consumption can be calculated precisely, because the amount of thread a stitch uses is a function of its geometry. Each stitch class has a formula giving consumption per inch of seam; multiply by seam length and you have total thread. Here are the variables, the equations for the common stitch classes, and a worked example.

The variables

Each formula is built from a small set of measurable inputs:

The identity N × S = 1 is what collapses the raw geometric formulas into the clean per-inch versions below.