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UK to US Shoe Size: Everything You Need to Know

6 min read  ·  Sizing guides

UK shoe sizes look deceptively similar to US sizes — close enough that people often assume they're interchangeable, or that the difference is trivial. In practice, buying a UK-sized shoe at what you think is your US size is one of the more common ways to end up with a pair that doesn't fit.

The relationship between UK and US sizes differs depending on whether you're looking at men's or women's sizing, and the offsets are easy to mix up. Here's a clear breakdown.

Men's UK to US: Half a Size Up

For men's shoes, the conversion is straightforward: US = UK + 0.5. A UK men's 9 is a US men's 9.5. A UK men's 10 is a US men's 10.5. The offset is consistent across the size range.

Men's UK to US reference:

To go the other way (US to UK), subtract 0.5. Your US men's 10 is a UK 9.5.

Women's UK to US: Two Sizes Up

Women's UK sizing has a larger offset from US sizing. US women's = UK women's + 2. A UK women's 5 is a US women's 7. A UK women's 6 is a US women's 8.

Women's UK to US reference:

Why Is the Women's Offset So Much Larger?

The US and UK women's sizing systems developed independently and landed on different number scales for the same range of foot sizes. There's no logical formula connecting them — it's a historical accident that stuck. The most practical way to think about it: UK women's sizing starts at smaller numbers than US women's for the same foot, and the gap widens slightly as you move up the size range.

This also means that mixing up men's and women's context when converting UK to US is an easy way to land two full sizes off. If you're buying a women's shoe from a UK site and accidentally use the men's conversion, you'll order a shoe that's two sizes too small.

Why the Shoe Insole or Box Often Shows Both

If you're buying a shoe in the UK or from a UK retailer, you'll almost always see both the UK size and the EU size on the shoe tongue, insole or box. Many brands also include the US size. When all three are shown, always use the EU size as your cross-reference if you're unsure — EU sizes are consistent and don't have a gender split, so they're the most reliable anchor point when converting between systems.

Kids' UK to US Sizing

Kids' UK to US sizing is generally offset by about 0.5 to 1 size, depending on the age range. For younger kids (up to about UK 10C), the offset is smaller. For big kids (UK 3Y to UK 6Y), the offset is closer to the adult men's pattern (+0.5). As with adults, the safest approach is to use the EU size or CM measurement and match against the brand's chart rather than relying on the number offset alone.

Buying from UK Retailers as a US Customer

If you're in the US and buying from a UK site — JD Sports UK, END Clothing, Foot Asylum — most of them will show EU sizes as an option and sometimes US sizes too. If US sizes are shown, just order your US size. If only UK sizes are shown, apply the conversion above.

One thing to watch for: some UK sneaker listings use men's sizing for what are technically unisex shoes (e.g., Nike Air Force 1, Adidas Samba, New Balance 550). Women buying these styles should use the women's UK-to-US offset and then apply the additional 1.5 size adjustment for the gender difference. It sounds complicated but it reduces to: if you're a US women's 8, look for UK size 5 in a unisex listing.

Convert any UK size to US, EU, CM or Korean sizing instantly — for men's, women's and kids'.

Open the UK to US converter →

UK Sizing and EU Sizing: How They Relate

UK sizes and EU sizes are both based on physical foot length, just on different scales. The EU system (Paris Points) increments in 2/3 of a centimetre per size. The UK system increments in one barleycorn (1/3 of an inch, approximately 8.5mm) per size. Because one barleycorn is close to but not exactly the same as one Paris Point, the UK-to-EU conversion also doesn't produce clean whole numbers.

A UK men's 9 is EU 43. A UK men's 10 is EU 44. That's a clean-looking conversion, but at other sizes you get EU 42.5 and EU 44.5, which can be confusing if you're comparing across brands. Again, using CM as the common language solves this cleanly — your foot length in centimetres doesn't change regardless of which conversion chart you're reading.

Disclaimer: Size conversions are a guide. Actual fit varies between brands and models. Always verify against the brand's own size chart before ordering.