Quick answer: EU, US, and UK shoe sizes use different scales, and none of them convert with a simple fixed offset across the whole range. A US 9 is roughly a UK 8 and an EU 42, but the safest method is always measuring your foot in centimeters and matching that to the brand's own conversion chart, not applying a generic formula.
Buying shoes from a brand based in a different sizing system is one of the most common ways people end up with the wrong fit, even when they've ordered their "usual" size.
Why the systems don't line up cleanly
US, UK, and EU sizing scales were developed independently, using different base units and increments. EU sizing is based on the Paris point system (roughly two-thirds of a centimeter per size), while US and UK sizing use their own separate scales with different zero points for men's, women's, and kids' sizing. This is why a single offset number, like "just add 33," only works approximately, and often breaks down at the small or large ends of the range.
Rough conversion reference
| US (Men's) | UK | EU | Foot length (cm) |
|---|---|---|---|
| 7 | 6 | 40 | 25 |
| 8 | 7 | 41 | 25.7 |
| 9 | 8 | 42 | 26.7 |
| 10 | 9 | 43 | 27.3 |
| 11 | 10 | 44 | 28.3 |
Women's sizing typically runs about 1.5 sizes higher on the US scale than the equivalent men's size for the same foot length, which is a separate common source of confusion when converting between men's and women's charts.
The one method that's actually reliable
Skip converting size number to size number entirely. Measure your foot length in centimeters (standing, end of day, longest toe to heel), then match that measurement directly to the brand's own size chart. Since brands vary slightly even within the same nominal system, this removes the guesswork that a generic conversion table introduces.
Common mistakes when converting
Assuming women's and men's sizing convert with the same offset across brands, since the gap varies. Using a conversion chart from one brand to estimate sizing for a completely different brand, since actual last shapes and size grading differ. And converting length alone without checking whether the brand also has a width dimension that matters for your foot specifically.
Where 8000Kicks fits
As a Portuguese brand shipping internationally, we size against EU measurements first and provide direct centimeter equivalents, so the conversion isn't left to a generic online chart that might not match our actual lasts.
Frequently asked questions
Is EU size 42 the same across every shoe brand?
Approximately, but not exactly. EU sizing follows a standard formula, but actual fit varies by last shape, so checking foot length in centimeters against the specific brand's chart is more reliable than assuming size 42 fits identically everywhere
How do I convert US women's sizes to EU sizes?
US women's sizing generally runs about 1.5 sizes higher than the equivalent US men's size, then converts to EU using the standard men's-to-EU formula from that adjusted number. Measuring in centimeters and matching to the brand's own chart avoids compounding conversion errors.
Why did I order my usual size and it still didn't fit?
Most often this happens because "usual size" was set with one brand's specific last, which doesn't transfer directly to a different brand's sizing, even within the same nominal system.
Related Reading
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