How to Grade Sizes for Clothing: A Practical Guide
How to grade sizes for clothing — understanding grade rules, creating graded measurement charts, and maintaining fit consistency across sizes.
What size grading is
Size grading is the process of scaling a garment pattern up and down from a base size to create a full size range. It is not simply making everything bigger or smaller proportionally — different measurements grade at different rates to maintain fit and proportion across sizes.
For example, when grading a t-shirt from size M to size L, the chest might increase by 2 inches while the body length increases by only 1 inch. If you scaled everything proportionally, larger sizes would be too long.
Standard grade rules
Grade rules define how much each measurement changes between sizes. While brands customize their grading, industry standards provide a starting point:
Common grade increments (tops, in inches)
| Point of Measure | Grade (per size) |
|---|---|
| Chest width | 1.5 - 2 |
| Body length | 0.75 - 1 |
| Shoulder width | 0.5 - 0.75 |
| Sleeve length | 0.5 - 0.75 |
| Neck opening | 0.25 - 0.5 |
| Hem width | 1.5 - 2 |
| Armhole depth | 0.25 - 0.5 |
Building a graded measurement chart
Start with your base size — typically size M for standard ranges or size L for extended ranges. Fit your base size on a fit model and confirm all measurements. Then apply your grade rules to scale up and down.
AI tools can automate grading calculations. When you create a tech pack with Skema3D, the measurement chart is automatically graded based on industry-standard rules for the garment type.
Common grading mistakes
The most common grading mistakes:
- Grading all measurements at the same rate — different body areas need different grade rates
- Not testing extreme sizes — always check your smallest and largest sizes on a fit model
- Forgetting to grade details — pocket size, label placement, and trim lengths also need grading
- Inconsistent tolerance specifications — tolerances should be the same across all sizes