Definition
A size chart is the table that translates a garment's labelled sizes into real measurements in centimeters or inches. It is the only reason a designer in Berlin, a factory in Portugal and an employee in Chicago can agree on what "medium" actually means. Without one, every order becomes a guess, and guesses turn into returns.
Definition
A size chart lists each available size alongside the measurements that define it. Those measurements are either body measurements, meaning the person the garment is cut for, or garment measurements, meaning the flat dimensions of the product itself. A typical t-shirt chart shows chest width, body length and sometimes sleeve length per size. For example, a men's medium tee might be listed as 52 cm chest width measured flat, 72 cm body length from the high point of the shoulder. Those two numbers tell a buyer far more than the letter M ever will.
How a size chart works
Size charts are built from a base size and a set of grading rules. The maker picks a middle size, often M, defines every point of measure on it, then steps each measurement up and down by a fixed increment to create the other sizes. Chest width might grade by 2 cm per size while body length grades by 2.5 cm. That grading logic is what makes the whole range feel consistent on a body rather than just bigger in every direction.
Two details cause most of the confusion. The first is body versus garment measurement. A 100 cm chest on a body chart and a 52 cm flat chest width on a garment chart can describe the same shirt, because the flat measurement covers half the circumference plus ease. Read the header before you compare anything. The second is tolerance. Cut and sew production always has a margin, usually 1 to 2 cm per point of measure, so two identical shirts can differ slightly and still pass quality control.
Sizes are also not standardized across brands or regions. A European M, a US M and an Asian M can be three different garments. Fit blocks shift the numbers further, since a slim fit and a relaxed fit in the same nominal size are built on different chest and length values. This is why the chart, not the letter, is the source of truth, and why it belongs in every tech pack you approve.
Size charts in branded merch
- Collecting sizes before you order. Publish the size chart with your internal sizing survey. People pick against real centimeters instead of memory, which makes your size run far more accurate and leaves less dead stock in the storage room.
- Onboarding and global teams. New hires and colleagues in other regions cannot try anything on. A clear chart with a short "how to measure" note is the difference between a welcome pack that gets worn and one that sits in a drawer.
- Webshops and gift portals. Every product page in an employee store or client gifting portal needs its own chart, tied to that exact product. One generic chart across a catalog of different suppliers is how you generate a return queue.
A size chart is a table that converts named sizes such as S, M or L into precise body or garment measurements, so people can pick the right fit before they order.
5 tips to elevate your Size chart strategy
| Tip | Steps |
|---|---|
| Label the method | State clearly whether the numbers are body measurements or flat garment measurements, and in which unit. |
| Chart per product | Attach the supplier's own chart to each item rather than reusing one generic table across the catalog. |
| Add a how-to-measure line | Tell people to measure a shirt they already own and love, laid flat, then match it to the chart. |
| Note the tolerance | Publish the accepted margin per point of measure so nobody flags a 1 cm difference as a defect. |
| Verify against the sample | Measure the physical sample yourself and confirm it matches the chart before the bulk run starts. |
Key Terminologies
Frequently Asked Questions
How do I read a size chart?
Check the header first to see whether the numbers are body measurements or flat garment measurements. Then find your key value, usually chest width, and read across to the matching size.
What is the difference between body and garment measurements?
Body measurements describe the person, so a 100 cm chest means the circumference of the torso. Garment measurements describe the product laid flat, so a 52 cm chest width means one side of the shirt from armpit to armpit.
Why do sizes vary between brands?
Every brand uses its own base size and grading rules, and regional standards differ between Europe, the US and Asia. A medium is a marketing label, not a fixed measurement, which is why you always compare charts rather than letters.
What is size tolerance?
Tolerance is the accepted production margin, typically 1 to 2 cm per point of measure. Two garments of the same size can differ slightly within that margin and still meet the specification.
Do I need a separate size chart for every product?
Yes. Charts are specific to a product and its fit block, so a hoodie, a polo and a tee from the same range will each have their own numbers.
