Why Sizes Differ Between Brands, and How to Order Without Guessing

There is no enforced standard for clothing sizes. A label size is the brand's opinion, and it varies between brands, between countries, between ranges within one brand, and over time. Ordering by label size is guessing.

Body measurements versus garment measurements

Brands publish one of two things, and confusing them causes most sizing errors:

• Body measurements — the size of person the garment is designed for. The garment itself will be larger, by an amount the brand chooses.
• Garment measurements — the actual flat dimensions of the item. Far more useful, and increasingly published.

Where garment measurements are given, compare them against something you own that fits. Lay the item flat, measure across the chest, the waist, the length and the sleeve, and match. This is the single most reliable online sizing method and it works across every brand.

Take your own measurements once

Chest, waist, hips, inside leg, sleeve length from centre back, and shoulder width. Write them down. Measure over light clothing with the tape level and not pulled tight. Redo them occasionally.

With these, a brand's chart becomes usable rather than decorative.

Why the same size fits differently

• Vanity sizing. Some brands label generously. This drifts over time.
• Different target fits. A brand cutting for a slim fit and one cutting for a relaxed fit will size the same chest measurement differently.
• Country conventions. Sizes converted between markets are approximate, and conversion charts disagree with each other.
• Fabric. A stretch fabric fits a wider range than a rigid one, so the same measurements behave differently.
• Shrinkage. Some cotton garments are sold pre-shrunk and some are not.

Use the reviews for sizing, not for stars

Repeated comments saying an item runs small or large are the most reliable sizing information available, more so than the chart. Reviews mentioning the reviewer's height and usual size are the most useful of all.

Make the return policy part of the plan

Ordering two sizes and returning one is a legitimate strategy where returns are free, and an expensive one where they are not. Before ordering, check:

• Who pays return postage.
• The return window, and whether it starts at order or at delivery.
• Whether sale items are returnable, which is a common exclusion.
• Whether tags must be attached, and the condition requirements.
• Whether exchange is possible or only refund, which matters for popular sizes that sell out.

For cross-border orders, check whether import duties are refunded on return, since often they are not and that turns a free return into an expensive one.

Before you order

Compare garment measurements against something you own, not your usual label size. Check the fabric composition for stretch, which widens the acceptable range. Check who pays return postage before ordering multiple sizes. And keep a note of which size worked in which brand, so the next order is not another guess.