Garment Grading Explained: Sizing Your Tech Pack Run

Garment grading is the process of taking one finished sample size and scaling it up and down into a full range of sizes — XS through XL, or 0 through 16 — by applying consistent measurement increments to each point of measure. Done right, grading is what lets a size XL fit a larger body the same way your size S fits a smaller one, with the proportions you designed intact. In a tech pack, grading lives in the measurement chart, and getting it wrong is one of the most expensive mistakes a new designer can make, because it shows up in every single unit you produce.

If you’re still getting oriented, it helps to first understand what a tech pack actually is and how the points of measure in a tech pack work, since grading is built directly on top of them.

What is garment grading?

Grading is scaling, not redesigning. You fit and perfect one base size — usually a medium or a size 8 — and then you grow and shrink that pattern into the rest of the run using fixed rules. The garment doesn’t change shape; it changes dimensions in a controlled, proportional way.

A quick definition of the term that does all the work here: a grade rule is the amount a specific point of measure changes between consecutive sizes. If your chest grows by 1 inch from S to M, and again from M to L, then “+1 inch chest” is your grade rule for the chest. Every point of measure — chest, waist, sleeve length, hem, armhole — gets its own grade rule, because they don’t all grow at the same rate.

This is the key insight beginners miss: a body doesn’t scale uniformly. A person two sizes larger isn’t simply 10% bigger everywhere. Their chest and waist grow more than their neck; their height (and therefore sleeve and body length) barely changes between adjacent sizes. Good grading reflects that reality, which is why each measurement carries its own increment rather than one blanket percentage.

How do grade rules work in a tech pack?

In practice, grading turns your single-column points of measure chart into a multi-column graded measurement chart, one column per size. Here’s the workflow:

1. Pick and perfect your base size. Fit your sample on a real fit model or a dress form until it’s right. This base size is the foundation — every other size inherits its errors, so fix them here first.
2. Assign a grade rule to each point of measure. Decide how much each dimension changes per size. Circumference measures (chest, waist, hip) usually carry the biggest increments; length and detail measures (neck, cuff, placket) carry smaller ones.
3. Apply the rules across the run. Add the increment for each size above the base and subtract it for each size below. The factory or your software fills in the full grid.
4. Sanity-check the extremes. Look hard at your smallest and largest sizes. Grading is linear, but bodies aren’t, so the ends of the run are where proportions break first.

Here’s a simplified illustration of three points of measure graded with a 1-inch chest rule, a half-inch sleeve rule, and a half-inch hem rule:

Point of measure	S	M (base)	L	XL
Chest width	19”	20”	21”	22”
Sleeve length	23.5”	24”	24.5”	25”
Hem opening	19.5”	20”	20.5”	21”

Notice the increments are different per row — that’s grading working as intended.

What is the difference between grading and a size chart?

People mix these up constantly. A size chart is the output: a finished table of garment measurements for every size that you hand to a factory (and sometimes publish for customers). Grading is the method that produces it — the base size plus the grade rules. You can’t have a trustworthy size chart without a deliberate grade behind it; if your sizes were eyeballed, the chart just hides the inconsistency.

It’s also worth separating grading from fit. Fit is whether the base size feels and looks right on a body. Grading is whether that fit holds across the run. A garment can be perfectly fit and badly graded — great in medium, sloppy in XL.

Common grading mistakes to avoid

A short checklist of what trips up first-time designers:

• Grading from an unfinished base. If the base size isn’t dialed in, you scale the flaw into every size. Lock the fit first.
• Using one increment for everything. A flat “+2 inches everywhere” ignores how bodies actually grow and produces sleeves that are too long on small sizes and necklines that gape on large ones.
• Forgetting detail measures. Pockets, plackets, collars, and trims may need to grow too — or deliberately stay fixed. Decide on purpose, don’t leave it to the factory.
• Skipping the extremes. Always pressure-test your smallest and largest sizes, where linear grade rules drift furthest from real proportions.

If you nail the base fit and assign thoughtful grade rules, the rest of your run will come back from sampling consistent — and that consistency is exactly what makes a factory take you seriously. You can see how this fits into a complete spec on our t-shirt tech pack page, or read more about how the whole document supports independent designers.

When you build a pack with techpacks.app, the graded measurement chart is generated for you from your base size and standard grade rules, so you can focus on getting the fit right instead of filling in a grid by hand. Preview your first pack to see how it comes together.

FAQ

What is garment grading in simple terms? Grading is the process of scaling one base size up and down into a full size run by applying set increments, called grade rules, to each point of measure. It keeps the fit and proportion consistent across every size.

What is the difference between grading and a size chart? A size chart lists the finished garment measurements for every size. Grading is the method you use to generate those numbers — the grade rules and increments that scale your base size into the rest of the run.

What is a grade rule? A grade rule is the amount a single point of measure changes from one size to the next, like adding 1 inch to the chest per size. Each point of measure has its own grade rule, and together they define the whole grade.

Do I need to grade every size myself? No. You define the base size measurements and the grade rules, and the factory or your tech pack software applies them across the run. Your job is to get the base size and the increments right.