Grading: one approved sample, a full size range.

Once a pattern fits well in one size, the next job is to make it in every other size you plan to sell. That is grading: scaling the pattern up and down so each size keeps the proportions, balance and character of the original. Done badly, a medium looks right and an extra large looks like a different garment. Done well, the whole range feels like one product.

This page explains what grading is, how size steps are set, why it is not simple scaling, what to decide before you start and how grading connects to sampling and bulk production. It is written for brands and buyers who want a consistent size run.

Grading takes a base size, usually the size that was fitted and approved, and creates the other sizes from it by adding or removing set amounts at specific points. Chest, waist, hip, shoulder width, sleeve length and garment length change by different amounts, and those amounts are called grade rules.

• Base size the size fitted and approved on the first sample.
• Grade rules the increments between sizes at each point of measure.
• Size range the sizes you plan to offer, such as XS to XXL.
• Fit logic how proportions change as the body size changes.

The result is a set of patterns, one for each size, that behave consistently.

Bodies do not scale evenly. A larger size is not simply a bigger copy of a smaller one: shoulders widen less than chests, sleeves lengthen by smaller steps than torsos and necklines need to stay in proportion to the face. If a pattern were scaled by a single percentage, the neck would become too wide in large sizes and too tight in small ones.

We set grade rules for your product type and fit style, and review them on sample garments, not only on paper.

Size steps are the differences between one size and the next, and they depend on the product and market. A t-shirt may step by 4 to 6 centimetres in chest between sizes. Children's sizes step by smaller amounts. Trousers step in waist and hip with a different logic from tops.

1. 01

   Decide your size range, from smallest to largest.

2. 02

   Decide whether you want standard or extended sizing.

3. 03

   Choose the size step for each point of measure.

4. 04

   Decide which sizes are fitted for approval.

5. 05

   Confirm the markets, since size conventions differ between countries.

We help you set these early, so that the pattern is graded once, correctly.

The largest and smallest sizes are where grading problems show first. A sleeve that is right in a medium may be too short in an extra large. A neckline that sits well in a small may gape in a large. We recommend sampling at least the base size and one extreme, and checking measurements on the finished garments.

If you plan an extended size range, or if your customers vary a lot in build, tell us at the start. It may be worth fitting more than one size before bulk, to be sure the proportions hold across the run.

Grading behaves differently across fabrics. Knits stretch, so grade steps can be smaller and the garment still fits across a wider body range. Wovens do not stretch, so grading needs more care to keep proportions accurate. Stretch fabrics need to account for how much the cloth gives at each size.

Shrinkage also matters, because a fabric that shrinks differently in length and width changes the finished measurements. We account for it when setting measurements, and we check the sizes after washing a sample.

Grading comes after the base pattern is approved. A first sample in the base size is fitted and revised until you are happy. The pattern is then graded across the size range, and the graded pieces are checked against the measurement chart. Bulk cutting uses the graded patterns, and quality checks measure finished garments against the size specification.

Because the graded patterns are kept on file, a reorder uses the same size run, and any later change, such as adding a size, can be made without starting again.

Tell us the garment, the size range, the markets and your base fit. We will respond in writing with questions and a suggested route. A sample in the base size is the first step, and made-to-order starts from 50 pieces per style. Our pattern making, custom sizing and sample development pages explain the neighbouring steps.