Size charts and grading: what your factory actually needs from you

“Do you have a size chart?” is the factory question that most exposes a new brand. It is also the one where a good answer prevents the most returns. So: what sizing actually is between a brand and a factory, and what to send.

What does a size like “M” mean to a factory?

“M” has no fixed meaning, a European fashion M, a US promo M, and a Japanese M differ by several centimetres. What production runs on is a measurement chart: points of measure down the side, sizes across the top, numbers in the grid, tolerances attached.

When customers say a brand “fits true,” they mean the brand defined its chart deliberately and its factory hit it consistently.

What sizing information should you send the factory?

Send one of three things: a full measurement chart with every point of measure, every size and tolerances; a base size plus grade rules, which the factory grades into a full chart for your approval; or a reference garment with the fit you want, which the factory measures, specs and grades for you to approve.

• A full measurement chart — every point of measure, every size, with tolerances. The professional standard; lives inside your tech pack.
• A base size + grade rules — one fully-specced size (usually M or L) plus the increments per step. The factory grades and returns the full chart for approval.
• A reference garment — the fit you want, in the mail. We measure it, spec it, grade it, and you approve the chart. Perfectly respectable for a first order.

Which sizing traps cause returns?

Four traps cause returns: treating “unisex” as neutral when it is a men’s block, mixing market size conventions such as UK and US women’s sizes, forgetting that kids’ sizes run on height and that safety rules change at 134 cm, and leaving tolerances unstated so that they become disputes.

• “Unisex” is a men’s block. If women are half your customers, a women’s cut is a size run, not a marketing label.
• Market conventions differ: a UK women’s 12 ≈ US 8; EU sizes run on different scales entirely. Label for your market, spec in centimetres.
• Kids’ sizes run on height (e.g. 122, 134 cm), and safety rules change at 134 cm, so kids’ grading is a compliance matter too. The kidswear rules.
• Tolerances left unstated become disputes: ±1.5 cm on chest is normal; agree the numbers before bulk, then measure the sample against them.

We grade in-house on Optitex CAD from any of the three starting points above — send a chart or a garment and you’ll get the full graded spec back for approval before sampling.