Approximate men's shoe size conversion between US, UK, EU and centimeters.
UK and US shoe sizes descend from an old English system based on the barleycorn, a third of an inch, which is why consecutive sizes differ by that odd amount and why half sizes exist at all. US men's sizes run one above UK; US women's sizes run about two above UK women's. European sizes use the Paris point, two-thirds of a centimetre, which is a different increment entirely and is why EU sizes do not map onto UK or US sizes in whole numbers.
The most reliable approach is to bypass the numbering altogether. Japanese sizing and the international Mondopoint system both state the foot length directly in centimetres or millimetres, which is what actually matters. Measure your foot in the evening, when feet are at their largest after a day of walking, and measure both — most people have one foot slightly longer, and shoes should be fitted to the larger one. Width is the factor most conversions ignore completely: two shoes of the same length in different widths fit quite differently, and a length conversion cannot capture that.
US men’s sizes are typically one number above UK. US women’s sizes are typically about two above the UK women’s equivalent. The systems share an origin, which is why the offsets are small and consistent.
Because they use the Paris point, two-thirds of a centimetre, while UK and US sizes use the barleycorn, a third of an inch. The increments differ, so conversions produce fractions rather than whole numbers.
In the evening. Feet swell over the course of a day, so a morning measurement can lead to shoes that become uncomfortable later. Measure both feet and fit to the larger one.
Often more, for comfort. Two shoes of identical length in different widths fit very differently, and most size conversions address length alone. Brands offering width fittings are worth seeking out if standard shoes pinch.