Shoe Size Conversion Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/10/2026
The European size is obtained with UK size + 33 (men and women). The US size, however, differs by gender: UK + 0.5 for a man, UK + 2 for a woman. A UK 7 men's size therefore corresponds to a European 40 and a US 7.5.
Explanation
Converting a shoe size between international systems is a frequent source of error, particularly between UK and US: the gap is not the same for men's and women's sizes. For a man, the US size exceeds the UK size by only about half a size; for a woman, the gap climbs to about 1.5 to 2 full sizes — ignoring this gender difference is the most common mistake when buying shoes on a foreign website. The European (EU) size is obtained more simply by adding 33 to the UK size, with no gender distinction. These conversions remain standard approximations, not an absolute guarantee: a shoe's actual fit varies noticeably from one brand to another (a "42" from one maker may fit differently from a 42 from another), so when in doubt about an important purchase, measuring foot length and consulting the brand's own size chart remains more reliable than a generic conversion. To convert a plain length rather than a size, see our length conversion calculator, and for jewelry, our ring size conversion calculator.
Example: UK size 7, men's
Inputs
UK size: 7. Gender: man.
Calculation
European size = 7 + 33 = 40. US size (men) = 7 + 0.5 = 7.5.
Result
A UK 7 men's size corresponds to a 40 in Europe and a 7.5 in the United States.
Frequently asked questions
Why is the UK–US gap not the same for men and women?
Because the UK and US sizing systems historically evolved with different size references by gender, without a single adjustment applying to both. It is a quirk inherited from industry conventions, not a logical rule deducible from a single calculation — hence the importance of specifying gender for a conversion to US sizes.
Are these conversions exact for all brands?
No, they are widely used standard approximations, but a shoe's actual fit (width, toe shape, arch) varies from one maker to another. For an important purchase, particularly online with no fitting possible, the brand's own conversion chart remains more reliable than this generic conversion.
How do you convert a children’s shoe size?
Children's sizes follow different scales and gaps from adult sizes, notably a separate British numbering system (often marked with a "C" for toddlers). This calculator is designed for adult sizes only; do not apply these same offsets to a children's size.