Shoe Size Converter

Four scales that do not quite line up

Buying shoes from another country means translating between systems that were never designed to agree. This converter takes a size in US, UK or EU numbering, or a foot length in centimetres, and shows the equivalent in all four across separate men’s and women’s charts.

Three rows are enough to show what the charts are doing.

Enter 27 cm on the men’s chart and the middle row is what comes back. A value well outside the chart is rejected rather than snapped to the nearest row: entering a US 30 does not quietly return the largest size available, it tells you the value is outside the chart, which usually means the wrong scale is selected.

Two patterns fall out of those numbers. UK men’s sizes run about half a size below US men’s throughout the range, a legacy of the two countries measuring from different starting points. And the men’s and women’s US scales are offset: a men’s US 8 is about 25.7 cm while a women’s US 8 is about 24.1 cm. On these charts a women’s 8 and a men’s 6 share that 24.1 cm length, a two-size gap, though 1.5 is the figure more commonly quoted — another reason to compare centimetres rather than numbers.

How the lookup works

Each chart is a table of rows, and every row carries the size in all four scales. The converter finds the row whose value in your chosen scale is closest to what you entered, then reads the rest of that row across. Because half sizes and brand variation mean an exact match is the exception rather than the rule, a near match is shown as the closest size rather than being refused.

The bounds check allows one average step of slack past either end of the chart, so a size just off the table still resolves to its neighbour while a wild value does not. That is what stops an EU number typed while the scale still says US from being dressed up as an approximate answer.

Why no chart can be exactly right

Shoe sizing is a convention rather than a standard. There is a European standard — the Mondopoint system, which simply states foot length and width in millimetres — but almost nobody sells shoes in it outside military and ski boot fitting. Everything else is inherited practice, and the increments differ: a full UK size is a third of an inch, while EU sizes step in two-thirds of a centimetre, so the two scales drift against each other rather than mapping cleanly.

On top of that, the last — the form a shoe is built around — varies by brand and by model within a brand. Two shoes labelled the same size from the same maker can fit differently if one is a running shoe and the other a boot. Width is a separate dimension that most numbering ignores entirely.

Treat any conversion, including this one, as a starting point, and check the maker’s own chart before ordering. The centimetre column is the one worth carrying between brands, because it is the only figure in the table that describes your foot rather than somebody’s numbering.