Grading: How One Pattern Becomes Twelve Sizes

Every garment in a size range descends from one original pattern. The process that produces the other sizes is mechanical, and its limitations explain a great deal of ordinary fit frustration.

The sample size is the only one designed

A designer develops the pattern in one size, fitted on a live model, adjusted until it hangs correctly.

Every other size is generated from that pattern by applying increments to specific points, a process called grading.

Nobody necessarily tries on the largest or smallest size before production, so the fit at the ends of the range is the output of arithmetic rather than of fitting.

Bodies do not scale uniformly

Grading adds a set amount at each point per size, which assumes proportions stay constant as bodies get larger.

They do not. Circumference generally increases faster than height, and the distribution of that circumference changes rather than expanding evenly.

A garment graded on the assumption of proportional scaling therefore fits progressively worse the further a size is from the sample, which is a mathematical outcome rather than neglect.

Some measurements barely change at all

Certain dimensions are close to fixed across a range: the distance from shoulder to the natural waist, the depth of an armhole, the position of a knee.

Grading rules acknowledge this by applying small increments to those points and larger ones elsewhere, but the increments are still uniform per size.

The result is that a person who is tall in one size and short in another finds that vertical proportions never line up, no matter which size they choose.

Extended ranges usually need a second pattern

Brands that fit well across a wide range typically develop more than one base pattern rather than grading a single one across everything.

A separate block for extended sizes allows proportional changes rather than uniform ones, which is why some brands fit noticeably better at the top of the range.

This costs development time and money, which is why it is more common among brands that specialize than among those adding sizes to an existing line.

What it means for a shopper

Fit is most reliable at or near a brand's sample size, and that size is usually in the middle of the range offered.

A person who consistently sits at one end will find that certain brands work and most do not, and the reason is which block the garments came from.

Finding a brand whose base pattern matches your proportions is more productive than searching for the right number, because the number was never the variable that mattered.