How to create a size chart and grade a clothing range

To create a size chart, pick a base size, define the points of measure, set the finished measurements for that base size, then grade every other size by fixed increments and agree a tolerance for each point. The factory builds the pattern in the base size, grades it, and makes a size set so you can check the whole range before bulk. Your customers see a simpler chart based on body measurements, which is a different document.

Two charts, not one

Brands often mix up two documents that do different jobs.

• The garment specification (the factory’s chart) gives finished garment measurements, measured flat, for every size, with tolerances. It is what the pattern is built to and what an inspector checks.
• The customer size guide tells shoppers which size fits their body. It lists body measurements such as chest girth and height.

International standards separate them the same way. The Swedish Institute for Standards’ summary of ISO 8559-2 says its size designation system is based on body measurements, not garment measurements, and that garment measurements are normally chosen by the designer and the manufacturer. ISO published a second edition of ISO 8559-2 in 2025. Mixing the two is the cause of a common complaint: a customer with a 100 cm chest buys a tee whose chest measures 100 cm, and it fits like a second skin, because the garment needs ease to be comfortable.

Choose a base size

The base size, also called the sample size, is the size the pattern is first made and fitted in. Most brands choose a size in the middle of their range, usually M for a men’s or unisex tee, because grading outwards from the middle keeps errors smaller at both ends than grading from S all the way up to XXL.

Fit your base size on a real person whose measurements match your target customer, not on whoever is nearby. Record that person’s body measurements, so that later fit sessions use the same reference. If your customers are mostly larger than the middle of your range, some brands choose a larger base size for that reason.

Define the points of measure

A point of measure, often shortened to POM, is a named measurement taken in a defined way. The definition matters more than the number: “chest” means nothing until you say where and how it is measured. For a tee, a typical set is:

• Body length from the high point of the shoulder (where the shoulder seam meets the neck rib) to the hem.
• Half chest, measured flat straight across, a set distance below the armhole, such as 2.5 cm.
• Half hem (bottom width), measured flat across the hem.
• Shoulder width, seam to seam.
• Sleeve length from the shoulder point to the sleeve hem.
• Half sleeve opening and half armhole.
• Neck width and front neck drop, and the neck rib height.

Write the method next to each point in the tech pack, ideally with a small sketch. Our guide on how to write a tech pack shows where the measurement chart sits in the full document, and the free template has the columns ready.

Build the base measurements from a garment you trust

Few new brands start with a blank sheet. The quickest reliable way to set base-size measurements is to measure a garment whose fit you already like, then adjust it on purpose.

1. Lay it flat on a hard table, seams straight, without stretching it. Knitwear stretches easily, so smooth it with the flat of your hand rather than pulling.
2. Measure every point twice with a flexible tape, in centimetres, and write down the average. If you have two of the same garment, measure both; the difference shows you how much variation a real factory produced.
3. Wash it and measure again. If a measurement changes after washing, note both values. The approved figure should be the one after washing, and the factory must allow for the shrinkage in the pattern.
4. Mark your changes as numbers, such as “body length plus 3 cm” or “shoulder width minus 2 cm”, not as words such as “longer” or “less wide”.
5. Keep the reference garment and send it with the tech pack, so the pattern maker can see the shape your numbers describe.

Measuring someone else’s garment for reference is ordinary practice. Copying its artwork, labels or distinctive design details is not, so treat it as a fit reference only.

Grade rules: how sizes step up and down

Grading turns one pattern into a range. A grade rule is the amount a measurement changes between neighbouring sizes. The US Department of Labor’s O*NET profile for fabric and apparel patternmakers describes the job as creating a master pattern for each size in a range, using charts, computers or grading devices, and computing pattern dimensions by size while allowing for the stretch of the material.

The table below is an example to discuss with your factory, not a standard. The values are in centimetres for a regular-fit unisex tee, with M as the base size.

Three things in the example are worth copying as ideas:

• Not everything grades. Rib height, label position and hem depth usually stay the same in every size.
• Small points grade small. The neck grows much less than the chest, or the large sizes end up with wide, gaping necks.
• Break points. Some brands increase the chest grade at the largest sizes, as in the XXL column, because bodies do not grow in perfectly even steps.

Grading is only as good as the base fit. If the M does not fit, grading copies the fault into every size.

Tolerances: how much variation you accept

No sewn garment measures exactly the same twice. Fabric stretches, stitching varies and fabric shrinks slightly in finishing. A tolerance is the agreed range around each measurement within which a garment passes inspection. Tolerances belong in the tech pack, next to each point of measure, because an inspector checks against them.

As an example to agree, not a rule: plus or minus 1 cm on large measurements such as half chest and body length, and plus or minus 0.5 cm on small ones such as neck width, rib height and sleeve opening. Tighter tolerances cost more, because more garments fail. Looser tolerances save money but can make an S and an M overlap, which confuses customers. Set them per point, not one number for the whole garment, and ask the factory what it can hold in your chosen fabric.

Why a size set is sampled

A size set is one sample in each size, or in the smallest, base and largest sizes, made after the base fit is approved. It shows whether the grade rules work across the range before fabric is cut in bulk. The common failures a size set catches are a largest size that is too short for its width, sleeves that end at the wrong point on the smallest size, and a neck opening that grows too fast. Measure every sample against the chart, try the extremes on real people if you can, and correct the grade rules before bulk production. Our sampling and product development page explains where the size set sits among the other sample rounds.

Labelling sizes for international customers

Letter sizes such as S, M and L mean different things in different markets and to different brands, so the customer size guide does the real work. European standard EN 13402-3 designates sizes by body measurements in centimetres, with a primary dimension first and secondary dimensions after it, separated by a slash. For men and women, the primary dimension depends on the garment, such as chest or bust girth for upper-body garments, with body height in second position.

For your size guide, a sensible practice is:

• list body measurements (chest, waist, hip, height) for each size, in centimetres and inches;
• add a short fit note, such as “boxy fit: size down for a regular look”;
• publish key garment measurements too, such as chest width and length, for customers who compare with a garment they own;
• keep the chart the same from season to season unless you change the fit, and say so when you do.

Kidswear sizing

Children’s clothing is sized differently. The preview of EN 13402-3 states that for children, body height always stays in the first position, followed by secondary dimensions. That is why many children’s garments are labelled by height in centimetres or by age range. Grade rules for children also change with age, because proportions change as children grow, so a single grade rule rarely works from toddler to teenager.

Size labels also interact with safety rules. US federal rules treat children’s upper outerwear in sizes 2T to 12 with hood or neck drawstrings as a substantial product hazard, and the regulation notes that a garment labelled as larger than size L does not necessarily fall outside that range. Our kidswear page covers the safety and fabric points to settle before sampling.

What to do next

Measure the garment whose fit you like best, flat, in its size, and write down what you would change. Fill in the measurement section of the template with that base size and the grade you want, even roughly. Then send it to us through the quote request on our contact page. We reply within one working day and our sample room can build the pattern, grade it and make a size set for you to check.