Shoe Size Converter

Why shoe sizing has no single global standard

Unlike length or weight, shoe sizing was never standardised around a single international system — US, UK, and EU sizing all use different scales, different starting points, and in the US and UK's case, different scales for men's and women's shoes. This tool converts between all three systems, along with the foot-length-in-centimetres measurement that's the most reliable way to double-check any size conversion, since it's based on an actual physical measurement rather than a brand's sizing chart.

How each system is built

EU sizing is based on the Paris point system, where each size unit represents two-thirds of a centimetre of foot length, giving EU sizes a fairly direct (though not perfectly linear across brands) relationship to actual foot length in centimetres. UK sizing counts in whole and half sizes starting from a base historically tied to barleycorns (a unit equal to about a third of an inch) as the increment between sizes. US sizing runs on a similar barleycorn-based increment to UK sizing but starts counting from a different base point, and — confusingly — US men's and US women's sizing use different offsets from each other, so a "US size 9" means a different actual foot length depending on whether it's listed as men's or women's.

Why brand charts still vary

Even after converting between EU, UK, and US using the standard formulas, actual fit still varies between brands and shoe styles, because manufacturers apply their own lasts (the physical mould a shoe is built around) and sizing tolerances. This tool's conversions are accurate against the standard size-scale definitions, which makes them a reliable starting point, but if you're buying from a specific brand for the first time, checking that brand's own size chart — and their return policy — remains the safest approach for a first purchase.

Measuring foot length directly

The most reliable way to sidestep size-chart confusion entirely is to measure your foot length in centimetres directly (stand on a piece of paper, mark your heel and longest toe, then measure the distance) and use that centimetre figure with this converter, rather than converting from a size you already own in one system into another. This removes any ambiguity introduced by how a specific old pair of shoes happened to fit, and gives you a physical measurement to check against any brand's chart.

Where this tool helps

Online shoppers buying from an international retailer whose sizing doesn't match their home country's convention, travellers replacing shoes while abroad, and parents tracking a growing child's shoe size across different brands' charts all benefit from a quick, reliable size conversion, especially one anchored to an actual centimetre measurement rather than just size-number guesswork.

A note for growing feet

Children's feet grow quickly and unevenly, so re-measuring foot length every few months rather than relying on a previous conversion is the most reliable way to keep footwear properly sized, particularly since an ill-fitting shoe is harder for a young child to describe or notice than it is for an adult.