Shoe Size Conversion

How the shoe size conversion works

Every shoe size system measures the same thing, the length of your foot or the inside of the shoe, but each uses a different unit and starting point. That's why there's no neat formula that works for every system and every brand. The tool uses conversion tables instead, the same ones in our men's shoe size chart and women's shoe size chart, so the calculator and the charts always agree.

The US and UK scales step in thirds of an inch, while EU sizes step in two-thirds of a centimetre. Those steps don't line up, which is why one EU size can sit between two US half sizes, and why the women's columns show EU and UK ranges. Our explainers on Paris point sizing and Mondopoint sizing go into the history.

Men's shoe size conversion chart

Full half-size detail is in the men's shoe size chart and the country guides for US to UK, US to EU, US to Japan and US to Korea.

Women's shoe size conversion chart

The ranges are deliberate. Brands round women's conversions differently: one brand's US 8 is a UK 5.5, another's is a UK 6. When you buy, check which way the brand rounds.

Men's and women's sizes

For the same foot length, a US women's size is about 1½ sizes larger than the men's size. A women's 10 is roughly a men's 8½, and a men's 9 is roughly a women's 10½. This matters for unisex sneakers, which are often sized in men's, and for anyone shopping across both sections.

Men's shoes are also usually cut wider than women's in the same length. If you're a woman buying men's or unisex shoes, they'll feel roomier across the ball of the foot. Our women's to men's shoe size conversion has the full chart, and the guide to what D width means explains the width side.

UK sizing is the exception: many UK brands use the same number for men and women, so a UK 6 is a UK 6 in either section, even though the US numbers differ.

How to measure your foot for an accurate conversion

Converting a size you already wear works if that size fits well. If you're not sure, measure. You need a sheet of paper, a pen and a ruler or tape measure.

1. Measure late in the day, when your feet are at their largest.
2. Put the paper against a wall and stand on it with your heel against the wall, wearing the socks you'd wear with the shoes.
3. Mark the tip of your longest toe. It isn't always the big toe.
4. Measure from the wall edge to the mark in millimetres.
5. Repeat for the other foot and use the longer measurement.

Enter that number in the tool with "Foot length" selected. The tool rounds up to the first size whose foot length covers yours, because a shoe that's slightly long can be fixed with an insole and one that's short can't. Our guides on how to measure foot length and width and measuring shoe size without a Brannock device have photos.

Why conversions still go wrong

Even with a good chart, these trip people up:

• Brand lasts differ. A last is the foot-shaped form a shoe is built on. Two brands' size 9 can be half a size apart in length and very different in width.
• Style changes fit. Pointed shoes, boots, and shoes worn with thick socks need different room from sneakers. See what a size 10 heel means for how heels change fit.
• Half sizes aren't universal. Many EU brands sell whole sizes only; some sell halves. If you're between EU sizes, try both or read reviews.
• Width. If length is right but the shoe pinches, you need a wider fit, not a longer size. See what N, M, W and XW mean and what EE means in shoes.
• Kids' sizes use a separate scale. Use our kids' shoe size conversion and kids' shoe size chart by age.

Converting for running, ski and other sports shoes

• Running shoes are often sized half a size up from everyday shoes, to leave room for feet swelling on longer runs. Our running shoe size chart by brand and guide on measuring for running shoes cover it.
• Ski and snowboard boots use Mondopoint (foot length in millimetres). Measure your foot and use the boot maker's chart. See how to measure for ski boots.
• Ballet, pointe and dance shoes often run very differently from street shoes. See the pointe shoe size chart.

Buying shoes from another country

1. Find the brand's own size chart and look for foot length in cm or mm. That's the most reliable column.
2. Compare with your measured foot length, not your usual size.
3. Read reviews for "runs small," "runs narrow" or "true to size."
4. Check the returns policy for international orders before you buy.

To find your size in a different brand, try the shoe size recommender, which matches sizes across 13 brands using each brand's own chart.

If you're converting clothing too, see US to UK sizes for clothes. The US to UK size converter and US to EU size converter handle clothing sizes.

Worked examples

• A US women's 8 buying European heels. The chart says EU 38 to 38.5. Italian brands often run small, so she checks the brand's foot-length chart: her foot is 238 mm, which that brand puts at 38.5. She orders the 38.5.
• A US men's 10 buying Japanese sneakers. The chart gives 28 cm. Japanese sizes sit close to foot length, so if his measured foot is 26 cm, a 27.5 or 28 is right; he checks reviews for "runs small" before choosing.
• A UK women's 6 buying from a US site. UK 6 is about a US 8 to 8.5. The calculator gives both, and the US brand's foot-length chart decides between them.
• A woman buying men's running shoes. Her women's 9 converts to about a men's 7.5. Men's lasts are wider, which suits her slightly wide feet.

Moving from kids' to adult sizes

Children's shoe sizes run on their own scale and then restart. In US sizing, kids' sizes go up to about 13, then "big kids" sizes restart at 1 and run to about 7. A big kids' 5 is roughly the same length as a women's 6.5 and a men's 5. When a teenager moves into adult shoes, measure the foot and use foot length rather than the old size. Our kids' shoe size conversion covers the switch.

If you sell shoes online

Size and width are among the top reasons shoes are returned. On your product pages:

• Show foot length in cm or mm for every size, alongside US, UK and EU.
• Say how each style fits: "runs half a size small," "narrow fit."
• Show width options clearly if you offer them.
• Link to a measuring guide or tool right next to the size selector.

Our guide to size chart best practices for shoe stores covers the setup, and the free shoe size chart generator creates a branded chart image.

Frequently asked questions

Sources and standards

1. ISO 9407:2019, Shoe sizes: Mondopoint system of sizing and markingDefines shoe sizing by foot length and width in millimetres.
2. Paris point systemEU shoe sizes step in Paris points of two-thirds of a centimetre.
3. US and UK shoe size scalesBoth step by a barleycorn (one-third of an inch) per full size, from different starting points.
4. Tailor Size Guide men's and women's shoe size chartsThe conversion tables used by the calculator.