Shoe Size Conversion US, UK, and EU: Charts, Brand Differences, and Measuring
A US 9 is not a UK 9, a EU 42 is not the same in every brand, and a size that fits in one shoe can pinch in another. This guide explains how US, UK, and EU sizing actually work, gives conversion charts you can use, and shows how to measure your feet in centimetres — the one number that does not change between systems.
Why Shoe Sizes Are So Confusing
Shoe sizes look like a standard, but they are not. There are three main systems in common use — US, UK, and EU — and each one measures something slightly different, starts from a different zero point, and steps in different increments. On top of that, each brand builds its shoes on its own last, the foot-shaped form the shoe is made on, so a size 9 in one brand can be longer, wider, or shaped differently from a size 9 in another. The result is that size conversion charts are a useful starting point, but they are never a guarantee, and the only number you can rely on across brands and systems is the length of your foot in centimetres.
The confusion has a history. UK sizing is based on the barleycorn, an old unit equal to a third of an inch, and it counts in thirds of an inch from a zero point that is not the same as the US zero point. US sizing is similar but starts from a different zero, which is why a US men's 9 is roughly a UK 8. EU sizing is based on the Paris point, equal to two-thirds of a centimetre, and it counts in two-thirds of a centimetre from a zero that is different again. None of these systems was designed to convert neatly into the others, and the half sizes and the differences between men's and women's sizing add further complications. Understanding that the systems are approximate is the first step to using them well.
US, UK, and EU: How Each System Works
US sizing comes in men's and women's versions, and they are offset from each other: a US women's 9 is roughly a US men's 7.5, a difference of about one and a half sizes. The steps are a third of an inch, about 8.5 millimetres, per full size, and half sizes exist in most ranges. UK sizing also has men's and women's versions, and they are offset in a similar way, though the offset is smaller. The UK steps are also a third of an inch, but the zero point is different, so a UK 8 is roughly a US men's 9 and a US women's 10.5. EU sizing is unisex in the number itself, but the same EU number can fit differently in a men's and a women's shoe, because the last is different. EU steps are two-thirds of a centimetre, about 6.7 millimetres, per size, which is a smaller step than the US and UK full size, so EU sizing is more granular — but not every brand offers half EU sizes, and some brands round differently.
The practical consequence is that conversion charts disagree with each other. One chart will tell you a US men's 9 is a EU 42.5, another will say 43, and both can be right for different brands, because brands round to different EU numbers and build on different lasts. When you see a conversion chart, treat it as a guide to the nearest size, not as a precise translation. The brand's own size chart, which gives the foot length in centimetres for each size, is always more reliable than a generic conversion chart, because it is based on the brand's own last. If a brand gives a centimetre measurement, use it. If it does not, measure your foot and use a generic chart as a starting point, then check the return policy before you order.
Conversion Charts
The charts below are the most commonly used conversions for adult sizes. They are a starting point, not a guarantee, and you should always check the brand's own chart where one is available. Men's and women's sizes are listed separately, because they are offset from each other in the US and UK systems.
| US Men | UK Men | EU | Foot length (cm) |
|---|---|---|---|
| 7 | 6 | 40 | 25.0 |
| 8 | 7 | 41 | 25.7 |
| 9 | 8 | 42.5 | 26.7 |
| 10 | 9 | 44 | 27.5 |
| 11 | 10 | 45 | 28.3 |
| 12 | 11 | 46 | 29.2 |
| 13 | 12 | 47.5 | 30.0 |
| US Women | UK Women | EU | Foot length (cm) |
|---|---|---|---|
| 5 | 3 | 35.5 | 22.0 |
| 6 | 4 | 37 | 23.0 |
| 7 | 5 | 38.5 | 24.0 |
| 8 | 6 | 39.5 | 24.8 |
| 9 | 7 | 41 | 25.7 |
| 10 | 8 | 42 | 26.5 |
| 11 | 9 | 43.5 | 27.5 |
Notice that the EU numbers in these charts are the most commonly quoted, but individual brands may list a US men's 9 as EU 42, 42.5, or 43. That variation is normal, and it is why the foot length column matters more than the EU column: if your foot measures 26.7 centimetres, look for a shoe whose insole length is about 27.5 to 28 centimetres, whatever the size number says. Children's sizing follows the same systems but starts from a smaller zero and grows faster, and it varies even more between brands, so always measure a child's foot in centimetres — our kids' shoes guide explains how.
Measuring Your Feet in Centimetres
Measuring your feet is the single most useful thing you can do before buying shoes online, and it takes five minutes. Stand on a piece of paper wearing the socks you will wear with the shoes. Have someone else trace around your foot if possible, because tracing your own foot while standing shifts your weight. Mark the longest point at the heel and the toe, and measure the distance between them in centimetres. Do the same for width, across the widest part of the forefoot. Do both feet, in the afternoon when they are largest, and use the larger foot's measurements.
Once you have the length, add about 1 to 1.5 centimetres for the space your toes need — the thumb's width of room at the front of the shoe. The result is the insole length you need. Compare that number with the brand's size chart, which usually gives the foot length or the insole length for each size. If the brand gives foot length, match your foot length directly. If it gives insole length, match your foot length plus the 1 to 1.5 centimetres. If the brand gives neither and only gives US, UK, or EU sizes, use the conversion charts above as a starting point and check the return policy. Keep a note of your measurements in centimetres — it is the one number that stays useful whatever brand or system you are buying from.
Brand Differences: Why the Same Size Fits Differently
Even with a perfect conversion, the same size fits differently between brands, because each brand uses its own last. Some brands are known for running narrow — many European fashion brands, for example — while others are known for running wide, such as several American comfort and running brands. Some brands run long, so you need a half size smaller than usual; others run short, so you need a half size larger. These tendencies are consistent enough that regular buyers learn them, but they are not printed on the box, and they change when a brand redesigns a model. The honest way to learn a brand's fit is to try it on, and the second-best way is to read reviews that mention fit: if many reviewers say a shoe runs small, believe them.
Width adds another layer. US brands often offer wide and narrow fittings, labelled with letters — D is standard for men, B for women, 2E is wide, and so on — while most European brands do not offer width options and build width into the last. That means a European shoe in your usual EU size may be too narrow even if the length is right, and a US shoe in your usual US size may be the right length but the wrong width. Our wide and narrow feet sizing guide explains the width system in full. When you buy from a brand for the first time, check whether it offers wide fittings, read the fit reviews, and make sure the return policy allows a free exchange — that is the safety net that makes trying a new brand low-risk.
Buying Online: A Practical Method
Buying shoes online works well if you follow a method. First, measure your feet in centimetres. Second, check the brand's own size chart and find the size that matches your measurement. Third, read the fit reviews for that specific model, looking for comments about whether it runs large, small, narrow, or true to size. Fourth, check the return policy: free returns or free exchanges make the risk negligible, and a brand that charges for returns is a brand to be careful with. Fifth, order one pair first, not two, and wear it indoors for a day before you decide. If it fits, keep it. If it does not, exchange it for a different size rather than a different model — the model is probably right, the size is wrong.
There are two situations where online buying is riskier. The first is buying a shoe you have never tried, from a brand you have never worn, in a size you have only guessed from a conversion chart. The risk is manageable if the return policy is good, but it is still a guess. The second is buying for someone else, particularly a child, where you cannot try the shoe on them first. In that case, measure their feet carefully, use the brand's chart, and order from a retailer with free returns. For gift buying, our holiday gift guide covers how to give shoes well, including how to handle sizing when you are not sure.
Size conversion checklist
- Measure both feet standing, in the afternoon, in your usual socks.
- Record length and width in centimetres; fit the larger foot.
- Add 1–1.5 cm to foot length for the insole length you need.
- Use the brand's own size chart first; generic charts second.
- Remember US 9 men is roughly UK 8 and EU 42.5 — but check the brand.
- Read fit reviews for the specific model before ordering.
- Check the return policy before you buy; order one pair first.
- Wear new shoes indoors for a day before committing.
The Bottom Line
Shoe sizes are a guide, not a guarantee. The systems disagree with each other, brands build on different lasts, and the same number fits differently from one shoe to the next. The way through the confusion is to measure your feet in centimetres, use the brand's own chart, read the fit reviews, and buy from a retailer with a good return policy. Do that, and the size on the box stops mattering — what matters is the fit on your foot. For the fit side of the same question, see our wide and narrow feet sizing guide, and for how fit changes with the type of shoe, our running shoe guide and boots guide.