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Grading Calculator — Grade Patterns Between Sizes
Calculate grading increments to resize a sewing pattern up or down between sizes.
How We Calculate This
Pattern grading resizes a pattern between sizes by shifting every edge by a set amount. This calculator reads the actual Big-4 / Misses body chart (Simplicity, Vogue, Butterick, McCall's) and reports the exact bust, waist and hip change between the two sizes you enter, then spreads it around the body. The direction is determined automatically from your current and target sizes.
Big-4 / Misses grade (per size step)
- Sizes 4–10: bust & hip about 2.5 cm (1") per size
- Sizes 10–12: bust & hip about 3.8 cm (1½") per size
- Sizes 12 and up: bust & hip about 5 cm (2") per size
- Waist grades a little less through the mid-range and widens to about 5 cm (2") from size 14 up
- Each "size" is a 2-number increment (e.g., 12 to 14)
The total change is spread evenly around the body, so each quarter-pattern piece moves by about a quarter of the figures above.
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates. Always verify quantities before cutting or purchasing fabric.