One Bust, Five Numbers — and Only the Collar Is a Measurement

Why the label drifts and the body does not

National numbers are not defined by any body of measurement, which leaves each brand free to decide what its own 38 means — and over decades the numbers have drifted downwards, the same garment carrying a smaller label than it once did. The phenomenon has a name, vanity sizing, and it is why a wardrobe can contain three sizes that all fit. The European response was a labelling standard written in centimetres of the body rather than in numbers: bust, waist and hip printed on the label as measurements, so that the garment describes who it is for instead of naming a size. It has never displaced the numbers, but it is why more and more labels carry a small pictogram with figures beside it — those figures are the part that means something.

Take three measurements once

Bust or chest at the fullest point, waist at the narrowest, hip at the widest, tape level and snug without pulling, over light clothing rather than over a coat. Write the three numbers down and you never have to guess a national size again: every brand chart is built on those same measurements, so the reliable move is to read the maker's own table rather than convert from a size you think you are. For a shirt, add the neck — measured where the collar sits, with a finger's slack — and for trousers the inside leg, which is the one length that no size number encodes at all.

Frequently asked questions

Why is a men's European jacket a 48 when the chest is 38 inches?

Because the European number is the chest measurement halved: 96 centimetres of chest divided by two is 48. The British and American number is the same chest expressed in inches, which is 38. Both describe one body, and the constant gap of ten between the columns is arithmetic rather than convention — which is why menswear conversion is reliable in a way womenswear conversion is not.

The letter sizes look simpler. Are they?

They are simpler and vaguer, which is a fair trade for a T-shirt and a bad one for a jacket. A letter covers a whole step of the grid and brands disagree about where each step begins, so an M from one maker overlaps an S and an L from another. Use letters for loose garments and numbers — or better, the measurements behind them — for anything that has to fit at the shoulder, the waist or the neck.

Are the offsets the same for every garment?

For tops and dresses they hold across the range, which is what makes a single conversion table usable. Trousers are the exception, because they are sold on two numbers in some markets — a waist and an inside leg, both in inches — and one number in others, so a French 40 in trousers converts to a waist measurement and a length that has to be chosen separately. When a chart offers only one number for trousers, it is describing the waist and leaving the length to the hem.