Grading is the process of scaling a pattern from one sample size across a full size range. It is not simple enlargement, because bodies do not scale uniformly.
Why proportional scaling fails
Between sizes, some measurements grow considerably, some grow slightly, and some barely move at all. Armhole depth, shoulder width and neck opening change far less than chest and waist. Scaling everything at the same rate produces garments that are technically larger and practically unwearable at the ends of the range.
Grade rules
A grade rule set specifies how much each point of measure changes between consecutive sizes. These rules encode a decision about your customer, so they deserve deliberate thought rather than a default.
Choosing a sample size
Grade outward from the middle of your range. Grading from an extreme accumulates distortion at the far end, which is where fit complaints originate.
Fit checks across the range
- Sample the base size and at least one size at each extreme
- Check armhole, shoulder and rise, not only circumference
- Confirm that trims and details still sit proportionally
- Verify that pocket and placket placement scales sensibly
Extended sizing is a design task
Adding larger sizes by continuing the same grade rules rarely works. Extended ranges usually need adjusted proportions, and often a separate block. Treat it as design work rather than an afterthought.