Grading
What is garment grading?
Grading is the process of scaling a garment's measurements from a base size up and down across a full size range, using consistent grade rules for each point of measure. It ensures a style fits proportionally at every size, not just the sample size.
How grading works
Grading starts from a base size (often a mid-range size). Each point of measure is assigned a grade rule, the increment it changes by between sizes. Applying those rules across the range produces the graded size chart the factory works from.
Grade increments are not uniform across every measurement, a chest may grade differently from a neck or a sleeve opening, which is why grade rules are defined per point of measure.
Why grading belongs in the tech pack
A tech pack without grading only describes one size. Including the graded chart lets a factory cut and sew the full range correctly, and prevents fit drift at the extremes of the size run.
Grading with SpecForm OS
SpecForm OS builds your measurement spec from the garment reference and supports grading that spec across sizes, keeping the base measurements and grade logic together in one editable pack you can export for production.
A worked grade, from base size to size run
Say your base size is a M with a 100cm chest, and you want a 4cm total grade between sizes, a common increment for a relaxed adult top. Because most charts record the chest as a flat, doubled measurement, that 4cm on the body becomes a 2cm change in the flat-measure value between each size.
Applying that rule across the run gives you the graded chest column. Each POM gets its own rule, so length, sleeve, and neck all move by their own increments at the same time:
- S chest: 96cm, M: 100cm, L: 104cm, XL: 108cm, from a 4cm body grade.
- Body length from HPS might grade at 1.5cm per size, not 4cm, because vertical and horizontal proportions scale differently.
- Neck width often grades in small steps, for example 0.5cm, so the collar does not balloon at the large sizes.
- Sleeve opening might grade 0.5cm to 1cm, tuned to the garment rather than copied from the chest rule.
Where grading goes wrong
The most common grading error is applying one flat percentage to every measurement. Real garments do not scale uniformly: a body gets wider faster than a neck does, and a sleeve opening barely moves while the chest steps up. Grade everything by the same rule and the small sizes look choked while the large sizes look boxy.
The second common error is grading past the range the block was designed for. A block drafted around a mid size stays proportional for two or three sizes in each direction, then starts to distort. If you need a wide size run, that is usually a signal to develop a second block rather than to keep stretching one grade rule to the edges.
FAQ
Common questions
What is grading in fashion?
Grading is scaling a garment's measurements from a base size across a full size range using grade rules for each point of measure, so the style fits proportionally at every size.
What is a grade rule?
A grade rule is the increment a specific point of measure changes by between consecutive sizes. Each measurement can have its own grade rule, and applying them across the range produces the graded size chart.
What is the difference between grading and pattern making?
Pattern making creates the shape of the garment at one base size. Grading takes that finished base pattern and scales it up and down across the size range using grade rules. Pattern making decides how the garment is built; grading decides how that same build changes size to size.
Do all measurements grade by the same amount?
No, and assuming they do is the most common grading mistake. Each point of measure gets its own grade rule. A chest might grade 4cm between sizes while a neck grades 0.5cm and a sleeve opening grades 1cm. Grading per point of measure is what keeps a style looking proportional at every size rather than just stretched.
How wide a size range can one grade cover?
A block usually holds its proportions for a few sizes either side of the base, then distortion creeps in at the extremes. For a broad range, technical designers often split into more than one block or adjust grade rules at the ends rather than applying a single linear rule across everything. Keep an eye on the largest and smallest sizes, since that is where fit drift shows up first.
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