Shoe size converter

Measure the foot, not the shoe

Shoe sizing has no international standard, so the only reliable input is the physical length of your foot. Everything else is a national approximation layered on top of it.

To measure: stand on a sheet of paper with your heel against a wall, in the socks you would wear with the shoes. Mark the tip of your longest toe — which is not always the big toe — and measure from the wall to the mark. Do both feet and use the larger; most people have a measurable difference. Measure in the late afternoon, since feet swell over the day by up to half a size.

Where the systems come from

• UK — based on the barleycorn, a medieval unit of one-third of an inch. Each full size is one barleycorn longer, which is why sizes step in thirds of an inch.
• US — the same barleycorn scale, offset. US men's sizes run about half a size above UK; US women's about two and a half sizes above UK.
• EU — the Paris point, two-thirds of a centimetre per size. Steps are smaller than the Anglo systems, which is why EU sizes have no halves in most ranges and why a single EU size can span two UK half-sizes.
• Mondopoint — foot length in millimetres. Used by ski boots and by several militaries. It is the only system that states a measurement rather than encoding one.

Last length versus foot length

A shoe is built around a last, which is longer than the foot it fits. The allowance is roughly 1.0 to 1.5 cm, needed because the foot lengthens under load and slides forward when walking. That is why the calculator shows a recommended shoe length above your measured foot length.

Different manufacturers use different allowances, which is a large part of why the same nominal size varies between brands. Running shoes typically allow more than dress shoes, since feet swell during exercise.

Why conversions never quite agree

Because the systems use different step sizes and different zero points, the mapping between them is not clean. A UK 8 might be EU 42 on one chart and 42.5 on another, and both can be defensible. Rounding then compounds the disagreement.

Add brand variation on top and the practical advice is unavoidable: use this as a starting point, then check the manufacturer's own chart if they publish one in centimetres. Many now do, and that figure is worth more than any conversion.

Width is the other half

Length is only one dimension, and for comfort it is often not the limiting one. US sizing marks width with letters — from AA (narrow) through B, D, EE to EEEE (wide) — while UK sizing uses F, G and H fittings. Most European brands offer a single width.

If shoes in your correct length feel tight across the ball of the foot, the answer is a wider fitting rather than a longer shoe. Going up a size to gain width makes the shoe too long, which causes heel slip and the foot to slide forward.

Common questions