How to Build a Size Chart for Your Clothing Brand

Sizing is where brands quietly lose money. Bad fit drives returns, kills reviews, and erodes trust faster than almost anything else. A clear, well-built size chart is how you prevent it — and it's more straightforward than it looks.

The building blocks

• Points of measure (POM) — the exact places you measure a garment: chest, body length, sleeve, shoulder, hem, and so on.
• Base size — the size you design and sample first (often M). Everything else grades off it.
• Grading — the increments you add or subtract between sizes at each POM.
• Tolerances — the allowed variance in production (for example ±1 cm), because no two garments are ever identical.

How to build one, step by step

• Pick your base size and your size range (e.g. XS–XXL).
• List your points of measure for the garment type.
• Measure a fit sample — or a reference garment whose fit you love.
• Apply your grading increments across the range at each POM.
• Add tolerances so production has a realistic target.
• Wash-test — fabric shrinks, so measure after washing, not just off the roll.

Standard vs custom sizing

You can start from a standard body-measurement chart (ISO and ASTM both publish standard body sizes) and adjust to your fit and audience — a streetwear brand runs oversized, a fitted women's line runs closer to the body. Watch regional differences too: US, UK and EU size numbering don't match, so state which you're using.

Common mistakes

• Designing without a defined base size, so nothing grades cleanly.
• Forgetting shrinkage — always wash-test before finalising.
• Tolerances too tight to manufacture, or so loose that sizes feel inconsistent.
• Copying a competitor's chart without checking it against your own fit sample and fabric.

We give you a base size chart to work from and grade it to your fit, and every style is sampled and wash-tested before bulk. See how sampling works and what goes in a tech pack.