Sewing pattern size calculator

How the sewing pattern size calculator works

The calculator uses the standard commercial size chart built into the Sewzy app's size finder, sizes 6 to 24. Each of your measurements is compared with its own column of the chart, and you get the smallest size whose number is big enough for you, with a quarter inch of tolerance. In practice a measurement a hair over a chart number still lands in that size, which matches how most people grade by eye.

Tops and dresses: choose by your bustSkirts and pants: choose by your hipWaist: shown for reference, because it is the easiest measurement to adjustSize = the smallest chart size where chart value ≥ your measurement − ¼ in

Tops and dresses go by the bust because the shoulders and chest are the hardest areas to change. Skirts and pants go by the hip because a hip that is too small cannot be fixed, while a waist can be taken in or let out, and an elastic waist forgives a lot. If your bust size and hip size are two or more sizes apart, the calculator suggests blending: cut the top size at the bust and draw a smooth line along the side seam to the bottom size at the hip.

The guide to choosing a sewing pattern size explains how to take the three measurements and why your shop size has little to do with it. Patterns in the Sewzy app list their own body measurements too, and the app's size finder uses this same chart, so the numbers match.

Related guides

• What size sewing pattern do I need?
• How to read a sewing pattern: symbols, grainline and notches explained
• How to find a sewing pattern from a photo