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.

Sizing is a chart, not a letter

“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 to send, three acceptable answers

• 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.

The traps that cause returns

• “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.