Shoe Size Conversion: US, UK, EU and cm — and Why Brands Never Quite Agree

A US men’s 9 is a UK 8, an EU 42.5 and fits a 26.5 cm foot — according to the standard chart. According to the shoebox in front of you: maybe. Shoe sizing is three incompatible historical systems plus per-brand variation, and the only brand-proof number is your foot length in centimeters. The shoe size converter handles both: chart conversion and foot-measurement lookup.

Why three systems exist (blame barleycorns)

UK sizing is medieval: one size = one barleycorn = 1/3 inch, counted from a size-zero of 4 inches (children) or 8⅔ inches (adults’ scale start). US sizing kept the barleycorn step but shifted the starting point — so US runs about one size higher than UK for men. EU sizing counts Paris points of 2/3 cm from zero, measuring the last, not the foot. And Japan ignored all of it and just uses foot length in centimeters — the approach ISO’s “Mondopoint” standard endorses, because it’s the only one that measures the actual foot.

The charts

Men:

US	UK	EU	Foot (cm)
7	6	40	24.8
8	7	41	25.7
9	8	42.5	26.5
10	9	44	27.3
11	10	45	28.2
12	11	46	29.0
13	12	47.5	29.9

Women:

US	UK	EU	Foot (cm)
6	4	36.5	22.4
7	5	37.5	23.3
8	6	38.5	24.1
9	7	40	25.0
10	8	41	25.9
11	9	42.5	26.7

Half sizes and the interactive lookup live on the converter page.

Measure your foot: the two-minute method that beats every chart

1. Late in the day (feet swell), stand on a sheet of paper with your heel against a wall, wearing the socks you’ll use.
2. Mark the tip of your longest toe — for many people that’s the second toe, not the big one.
3. Measure wall-to-mark in centimeters. Repeat for the other foot; use the larger (nearly everyone is asymmetric).
4. Enter the cm in the converter. Buying running shoes? Add ~0.5 cm of room.

Standing matters: feet lengthen under body weight by several millimeters versus sitting.

Why brands never quite agree

A size number describes the last — the foot-shaped form the shoe is built around — and lasts are a brand’s design signature: a “9” built on a narrow racing last and a “9” on a roomy comfort last are different shoes. Deviations of half a size between brands are completely normal, sneakers often run different from dress shoes within the same brand, and width (rarely labeled outside the US D/E/EE system) changes perceived size again. Practical protocol: know your cm measurement, check the brand’s own cm-based chart when it exists, and treat converted sizes as the starting guess.

Common shoe-size mistakes

1. Converting numbers instead of measuring feet — the chart can’t fix a brand’s last.
2. Using the smaller foot — always fit the larger one.
3. Morning measuring — feet are up to 0.5 cm shorter than at day’s end.
4. Assuming EU sizes are unisex-identical to US logic — EU is one scale; US men’s and women’s are two shifted scales.
5. Ignoring width — length-perfect shoes that pinch are a width problem, not a size problem.

Quick summary

Convert with the chart (US M 9 = UK 8 = EU 42.5), but trust your foot length in centimeters over any size number — measure both feet standing, late in the day, and add half a centimeter for running shoes. Brands deviate by up to half a size around every chart, so the shoe size converter’s cm mode is the reliable route.

Charts follow the standard published conversion; your measurements never leave your browser. Related: the ring size converter and bra size converter, and for the cm↔inch math itself, cm to inches.