Ordering shoes from another country is where most people discover that shoe sizing is not one system but several, built on different units, different starting points and different assumptions about what is being measured. A women’s 8 in the United States, a 6 in the United Kingdom, a 39 in Europe and a 25 in Japan can all be the same foot.
What each system is actually measuring
US and UK sizes descend from the English barleycorn — a unit of one third of an inch. Each full size is one barleycorn longer than the last. The two systems use the same increment and different starting points, which is why UK sizes run roughly 1.5 below US women’s and 1 below US men’s.
European sizes use the Paris point, two thirds of a centimetre per size. Because the increment is smaller, EU sizes move in smaller jumps, and there is often no half size at all.
Japanese and Korean sizes are the only ones that are immediately sensible: the number is the foot length in centimetres or millimetres. A 24.5 is a foot 24.5 cm long.
The conversion table
| US Women | UK | EU | Japan (cm) | Foot length |
|---|---|---|---|---|
| 6 | 4 | 36–37 | 22.5 | 22.5 cm |
| 7 | 5 | 37–38 | 23.5 | 23.5 cm |
| 8 | 6 | 38–39 | 24.5 | 24.5 cm |
| 9 | 7 | 39–40 | 25.5 | 25.5 cm |
| 10 | 8 | 40–41 | 26.5 | 26.5 cm |
Note the ranges in the EU column. They are not laziness — the Paris point does not divide evenly into the barleycorn, so a single US size genuinely straddles two European ones. Any conversion chart presenting an exact one-to-one match across all four systems is rounding and not telling you.
Measure the foot, not the old shoe
The only reliable input is a length in centimetres. Stand on a sheet of paper with your heel against a wall, mark the longest toe, and measure. Do it in the late afternoon, when feet are at their largest, and measure both — most people have one foot several millimetres longer, and shoes should fit that one.
Once you have a number in centimetres, every system converts from it directly, and you never have to trust what was printed inside a pair you bought years ago.
Why conversions still fail
- Brand variation. Within any single system, brands differ by up to a full size. Italian designer footwear runs notably small; American athletic brands run generous.
- Width is missing. Length is only one dimension. Two feet of identical length with different widths need different shoes, and most sizing systems say nothing about it.
- Last shape. The mould a shoe is built on varies enormously, which is why the same size fits differently in a pointed shoe and a round-toed one.
- Unisex sizing. Frequently labelled in men’s sizes, which adds another 1.5–2 size offset.
Where a specific person’s size is a useful reference point — for style comparison or because you are buying something a public figure was photographed in — indexed reference sites collect them. Indexed entries such as Jennifer Lopez Feet and Eva Longoria Feet record the size alongside the photographs, which is a faster comparison point than working backwards from a red carpet image.
Regional sizing conventions
Beyond the four main systems, several markets use local variants — Mexican sizing in centimetres, Australian women’s sizing following UK with its own quirks, and Chinese sizing in millimetres. Buying across borders regularly is easier when you know which convention the seller’s country uses, and a reference entry such as Kendall Jenner Feet will often list the figure in more than one system, which makes the regional difference concrete.
The practical rule
Know your foot length in centimetres. Convert from that, never from another country’s number. Then check the specific brand’s own chart, because the brand’s chart beats any universal one — and when it is between two sizes, take the larger and fit it with an insole.
