How to use this calculator
- Enter or choose start from.
- The uK updates as you type. Use Copy result or Share to keep it.
Method
UK ≈ 3 × foot (in) − 23; US men ≈ 3 × foot (in) − 22; US women ≈ 3 × foot (in) − 21; EU ≈ 1.5 × foot (cm) + 2; Mondopoint = foot length in mm
- foot
- heel-to-toe foot length; the shoe’s last is about 1.5 cm longer, which the constants already allow for
Worked example
- 27 cm ÷ 2.54 = 10.63 in.
- UK = 3 × 10.63 − 23 = 8.89, rounded to the nearest half size: 9. US men’s adds 1 (10); US women’s adds 2 (11).
- EU = 1.5 × 27 + 2 = 42.5. Mondopoint is the foot length in millimetres: 270.
A 27 cm foot is about UK 9, US men’s 10, US women’s 11 and EU 42.5.
What the result means
Treat the result as a starting point. Brands size their lasts differently, so the same foot can be an EU 42 in one brand and a 43 in another; check the brand’s own chart when it gives one.
Assumptions and limits
- Adult sizes. Sizes are rounded to the nearest half size.
- US women’s uses the scale two sizes above UK; some brands use US men’s + 1.5 instead.
- Width is not considered.
- Children’s sizes use different scales and are not covered.
- Brand and style (boots, running shoes, high heels) change the fit.
Questions
How do I measure my foot?
Stand on a sheet of paper with your heel against a wall, mark the tip of your longest toe and measure from the wall. Measure both feet in the evening and use the longer one.
Why is a UK size smaller than the US size?
Both count in barleycorns (⅓ inch), but the scales start from different points: US men’s is one size above UK, and US women’s is usually two above.