Pattern Grading Calculator

Estimate a pattern measurement at a different size using a per-size grade increment.

Known measurement at your base size (in)

Grade rule per size step (in)

Sizes to move (+ up, − down)

What a grade rule is

Pattern companies size a garment by drafting one base size, then "grading" it up and down by a fixed increment per measurement, per size — the grade rule. A common misses-sizing grade rule is around 1" per size at the bust/waist/hip circumference, but the exact number varies by brand, size range, and even by measurement (sleeve length grades by a much smaller increment than bust circumference).

How this calculator works

New measurement = base measurement + (grade rule × number of size steps). Moving down in size uses a negative number of steps and subtracts instead.

Where to find your actual grade rule

If the pattern includes a size chart with measurements for multiple sizes, subtract two adjacent sizes' measurements to get the real grade rule for that specific pattern and measurement, rather than guessing — grade rules for children's patterns, petite ranges, and plus-size ranges in particular often differ from standard misses grading.