Why Jacket Sizes Differ Between Brands

A medium is whatever a brand decides it is. There's no single standard that every brand follows, so your size can shift by one or even two labels between brands, and sometimes between product lines from the same brand. The fix is simple: know your measurements and check every brand's own chart.

Vanity sizing

Over the years, many brands have drifted towards putting smaller size labels on bigger garments, because people like buying a smaller number. It's most noticeable in women's clothing and fashion brands. The practical result: a jacket you bought in a medium ten years ago is no guide to a medium today, even from the same brand.

UK, EU and US labels

Shops in Ireland mostly use UK sizes, often with EU equivalents alongside. Buy online and you'll meet all three systems.

Men's jackets are usually labelled S, M, L or by chest size in inches (38, 40, 42). European tailoring often uses numbers such as 48, 50 and 52, which roughly correspond to UK chest sizes 38, 40 and 42.

Women's jackets use dress-style sizes. A common conversion looks like this, but brands vary, so treat it as a starting point:

General tendencies, not rules: US brands often cut more generously, and European outdoor brands often cut slimmer. Brands designed mainly for Asian markets frequently run smaller. Always check the chart rather than trusting the letter.

Fit blocks

Every brand builds its sizes from a base pattern, often called a block, shaped around a fit model: a real person with a particular height, build and posture who represents the brand's typical customer. Other sizes are scaled up and down from that pattern.

If your proportions are close to the brand's fit model, its jackets will tend to fit you well across the board. If they aren't (longer arms, broader shoulders, a shorter body), that brand may never quite work. Once you find a brand whose cut suits you, make a note of your size there and stick to its charts.

Unisex sizing

Unisex jackets are usually based on men's patterns. That means broader shoulders, a straighter body, narrower hips and longer sleeves than a typical women's cut. Many women find they need to size down, but check the hip measurement and sleeve length before you do, because those are where unisex jackets most often go wrong. For more, see our women's jackets section.

Outdoor brands vs fashion brands

Outdoor brands design around movement and layering. Expect longer sleeves, a longer back, shaped elbows and often room for a fleece underneath. Some describe their cuts with terms like athletic, active or regular, which mean different things at different brands.

Fashion brands design around the look, usually over a T-shirt or shirt. There's often less room for layers and shorter sleeves. So the same person can be a medium in an outdoor jacket and a large in a fashion jacket, or the other way round.

How to read a size chart

1. Use the right chart. Men's, women's or unisex, and the specific product line if the brand has more than one.
2. Work out whether it's body or garment measurements. Headings like "to fit chest" or "body measurements" mean body. Headings like "garment measurements", "flat" or "pit to pit" mean the jacket itself.
3. Watch for half measurements. A chest figure taken with the jacket laid flat is half the circumference, so double it.
4. For a body chart, compare your own measurements directly. The brand has already built in room.
5. For a garment chart, compare against a jacket you own that fits well. Our guide to how to measure yourself for a jacket shows how.
6. Read the fit notes. "True to size", "size up for layering" or "model is 185cm and wears M" are all useful clues.
7. If you're between sizes, let the shoulders and chest decide, and think about what you'll wear underneath.

Using reviews sensibly

Reviews are useful for sizing if you read them for patterns:

• Look for agreement. One person saying it runs small is an opinion. Ten people saying it is a pattern.
• Find people like you. Reviews that mention height, build and usual size are worth far more than "fits great".
• Check what they wore underneath. Someone who tried a winter coat over a T-shirt in August may think it runs large.
• Ignore the noise. Comments about delivery or colour tell you nothing about fit.

Returns

Check the returns policy before you order: how long you have, who pays postage, and whether the tags need to stay on. Ordering from outside the EU, including from Britain, can mean customs charges and slower, dearer returns, so read the small print.

If returns are free, ordering two sizes and sending one back is a reasonable way to settle it. Try both on indoors over your usual layers, do the movement tests, and keep the tags on until you're sure. Our guide to slim, regular and relaxed fit helps you read the fit descriptions, and how to choose a jacket that fits properly covers the whole process.