Women’s shoe size converter
Every size system starts from the length of a foot. This converter works the same way: it turns any size into a foot length, then into the other systems, using the method behind the ISO 19407 conversion standard.
Convert a size
Rounded to the nearest half size. Foot length is heel to longest toe, standing.
How we calculate
Every size is first turned into foot length in millimeters, then into each system with the formulas published for ISO 19407: UK = 3 × mm ÷ 25.4 − 23, US women’s = UK + 2 (some brands use UK + 2.5, the “common” scale), EU = 0.15 × mm + 2, Japan = foot length in half-centimeter steps. Brand lasts differ, so treat the result as a starting point, usually within half a size.
How the conversion works
Shoe sizes are a count of small steps, and each country counts in a different step. UK and US sizes step in barleycorns, a third of an inch. European sizes step in Paris points, two thirds of a centimeter. Japan and the international Mondopoint system skip the steps and write the foot length itself. A shoe is also longer inside than the foot, so every system adds an allowance before it counts.
We use the formulas published for ISO 19407, the international standard on converting between sizing systems, which starts from foot length in millimeters and includes a two-size allowance:
- UK = 3 × foot length (mm) ÷ 25.4 − 23
- US women’s = UK + 2 (the “standard” women’s scale; some brands use UK + 2.5)
- EU = 0.15 × foot length (mm) + 2
- Japan = foot length in centimeters, in half-centimeter steps
Two US women’s scales are in use. On the standard scale a US women’s size is two sizes above the UK number, so a UK 5 is a US 7. Some brands follow an older “common” scale that puts women’s sizes half a size higher, so the same UK 5 is labeled US 7½. If a brand’s chart disagrees with ours by exactly half a size, this is usually why. Choose the second option in the menu to convert from such a label.
The standard itself says its adult tables are a guideline, because the systems grew up separately and were never fully formalized. Lasts, the forms shoes are built on, vary by brand and style, and pointed toes or high heels change how a size fits. Use the result as a starting point and check the brand’s own chart and return policy before ordering.
Women’s size chart, US 4 to 13
Sizes in recall notices
Recall notices often name the sizes affected. 8 recalls in our archive that involve women’s footwear list sizes, for example “sizes 5 through 11” for The North Face Women’s Shellista V Mid Waterproof Boots. Imported styles sometimes give EU sizes only, which is where this chart helps. Browse women’s recalls to see them.
To get the foot length right, read how to measure your feet at home; for the history behind the numbers, see US, UK and EU women’s sizes explained.