Grade a pattern between any two sizes from your own base measurements, with per-measurement grade rules, a wider grade above L, and the amount to slash and spread at each pattern quarter.
Change the inputs that matter to your decision. Optional assumptions stay collapsed until you need them.
From the pattern you are actually grading. Anything left blank uses a sample value.
Tops graded up 1 size from M to L, from the sample measurements — enter your own for an accurate grade.
The grade rules apply to any pattern, but the base and target values shown come from a sample block until you enter the measurements of the pattern you are actually grading.
| Bust | 38" → 40"2" total · 2" per size · 1/2" at each pattern quarter |
|---|---|
| Waist | 32" → 34"2" total · 2" per size · 1/2" at each pattern quarter |
| Hip | 40" → 42"2" total · 2" per size · 1/2" at each pattern quarter |
| Shoulder width | 15 1/2" → 16"1/2" total · 1/2" per size · 1/2" at the piece |
| Neck width | 6 1/2" → 6 3/4"1/4" total · 1/4" per size · 1/4" at the piece |
| Armhole depth | 8 1/2" → 8 3/4"1/4" total · 1/4" per size · 1/4" at the piece |
| Sleeve length | 23 1/2" → 23 3/4"1/4" total · 1/4" per size · 1/4" at the piece |
| Centre back length | 27" → 27 1/4"1/4" total · 1/4" per size · 1/4" at the piece |
Grade rules here are typical industry increments. A specific pattern company's own grade rules take precedence, and a large grade across several sizes is better checked with a toile than trusted outright.
Practical notes about the inputs, assumptions, and result.
Because a grade is only useful applied to the pattern you actually have. Grade rules are increments, not absolutes: adding 2 inches to a bust is the same operation whatever the starting bust, but the target value is meaningless unless the base is yours. Sample values stand in until you enter your own, and the result says which it used.
A quarter of a girth change. A 2 inch bust grade is distributed across four pattern quarters — front and back, left and right — so each side seam moves by half an inch. Adding the full 2 inches at one seam is the most common grading mistake and produces a garment 6 inches too big.
Usually not. Most published size runs step girth measurements by half again above L, so a straight 2 inch grade from M to 4XL drifts badly by the top of the run. The extended grade is on by default and can be switched off if your pattern really does grade uniformly.
Yes. Set a target smaller than the base and every change is reported as a negative — the amount to take out at each point rather than add. The arithmetic is the same in both directions.
Because size runs are built around body circumference, not height. A bust grades 2 inches per size while a sleeve or centre back length grades a quarter inch, because someone two sizes larger is usually a similar height. Length changes for height are a separate alteration from grading.
One or two sizes is routine. Three or more changes proportions enough that armhole shape, dart placement, and neckline can all need redrawing rather than just spreading — grading moves points but does not reshape curves. Beyond two sizes, cut a toile before cutting your fabric.
Other tools in tailoring & sewing.
Estimate cloth for a garment at your fabric's actual width, with pattern repeat matching computed from the repeat length, nap layouts, shrinkage, lining, and a quantity rounded to what the shop will cut.
Choose a seam allowance for a garment and fabric, see the cloth a seam actually consumes, and convert a pattern from one allowance to another — with fractions reduced and metric paired the way patterns print it.
Convert the units a workroom actually uses: fractional inches, yards and metres, fabric weight between gsm and ounces per square yard, and iron temperatures by fibre.