In this Nike sizing guide:
Nike size conversion chart – Men’s shoes
| US size | UK Size | EU/FR Size | CM/JP Size |
|---|---|---|---|
| 6 | 5.5 | 38.5 | 23.7 |
| 6.5 | 6 | 39 | 24.1 |
| 7 | 6 | 40 | 24.5 |
| 7.5 | 6.5 | 40.5 | 25 |
| 8 | 7 | 41 | 25.4 |
| 8.5 | 7.5 | 42 | 25.8 |
| 9 | 8 | 42.5 | 26.2 |
| 9.5 | 8.5 | 43 | 26.7 |
| 10 | 9 | 44 | 27.1 |
| 10.5 | 9.5 | 44.5 | 27.5 |
| 11 | 10 | 45 | 27.9 |
| 11.5 | 10.5 | 45.5 | 28.3 |
| 12 | 11 | 46 | 28.8 |
| 12.5 | 11.5 | 47 | 29.2 |
| 13 | 12 | 47.5 | 29.6 |
| 13.5 | 12.5 | 48 | 30 |
| 14 | 13 | 48.5 | 30.5 |
| 14.5 | 13.5 | 49 | 30.9 |
| 15 | 14 | 49.5 | 31.3 |
| 15.5 | 14.5 | 50 | 31.7 |
| 16 | 15 | 50.5 | 32.2 |
| 16.5 | 15.5 | 51 | 32.6 |
| 17 | 16 | 51.5 | 33 |
| 17.5 | 16.5 | 52 | 33.4 |
| 18 | 17 | 52.5 | 33.9 |
| 18.5 | 17.5 | 53 | 34.3 |
| 19 | 18 | 53.5 | 34.7 |
| 19.5 | 18.5 | 54 | 35.1 |
| 20 | 19 | 54.5 | 35.5 |
| 20.5 | 19.5 | 55 | 36 |
| 21 | 20 | 55.5 | 36.4 |
| 21.5 | 20.5 | 56 | 36.8 |
| 22 | 21 | 56.5 | 37.2 |
Nike size conversion chart – Women’s shoes
The Nike women’s sizing chart works a bit differently – more specifically, the treatment of converting US into UK sizing.
| US size | UK Size | EU/FR Size | CM/JP Size |
|---|---|---|---|
| 2.5 | 13.5 | 32 | 19.9 |
| 3 | 1 | 33 | 20.3 |
| 3.5 | 1.5 | 33.5 | 20.8 |
| 4 | 1.5 | 34.5 | 21.2 |
| 4.5 | 2 | 35 | 21.6 |
| 5 | 2.5 | 35.5 | 22 |
| 5.5 | 3 | 36 | 22.4 |
| 6 | 3.5 | 36.5 | 22.9 |
| 6.5 | 4 | 37.5 | 23.3 |
| 7 | 4.5 | 38 | 23.7 |
| 7.5 | 5 | 38.5 | 24.1 |
| 8 | 5.5 | 39 | 24.5 |
| 8.5 | 6 | 40 | 25 |
| 9 | 6.5 | 40.5 | 25.4 |
| 9.5 | 7 | 41 | 25.8 |
| 10 | 7.5 | 42 | 26.2 |
| 10.5 | 8 | 42.5 | 26.7 |
| 11 | 8.5 | 43 | 27.1 |
| 11.5 | 9 | 44 | 27.5 |
| 12 | 9.5 | 44.5 | 27.9 |
| 12.5 | 10 | 45 | 28.3 |
| 13 | 10.5 | 45.5 | 28.8 |
| 13.5 | 11 | 46 | 29.2 |
| 14 | 11.5 | 47 | 29.6 |
| 14.5 | 12 | 47.5 | 30 |
| 15 | 12.5 | 48 | 30.5 |
| 15.5 | 13 | 48.5 | 30.9 |
| 16 | 13.5 | 49 | 31.3 |
| 16.5 | 14 | 50 | 31.7 |
| 17 | 14.5 | 50.5 | 32.2 |
Sizing basics: What to look for
Footwear sizing is one of the many things that make buying a running shoe tricky.
There are four different types of sizing – US, UK, EU and CM. Depending on the brand, the EU size might also be called FR (French), and the CM size as JP.
Not all brands follow a standard conversion across sizes. For examples, many US brands like Brooks, Saucony and Nike convert US sizes into UK sizes with a whole size difference (US 11 = UK 10), while brands like adidas, Hoka One One and New Balance apply a half-size conversion. (US 10 = UK 10.5). And here’s where it gets complicated; for smaller sizes such as US 4, 5, 6 and 6.5, Nike applies a half-size conversion from US to UK.
All this can make anyone’s head spin, so here’s an easy trick to tell what your shoe size is. For accurate results, measure the foot at the end of the day while wearing a pair of socks.
Out of the four, only the CM (short for centimeter) represents the actual length of the foot which is likely to fit in the shoe. When in doubt, always use the CM or JP size as your north star.
For example, if you know the size of your non-Nike running shoe, say a Mizuno, then see what the CM/JP size for that shoe is. Of course, the heel-to-toe length isn’t the only factor which determines the fit.
The actual fit depends on how the shoe is designed, including what kind of last (the fit profile) used. But the CM or JP is a reliable sizing guide, because it stands for actual length.
Here’s the Nike shoe size chart. If you’re swapping your existing Nike shoe for a Nike, then you’ll probably fit in the same size.If you’re switching brands, then sticking to the same JP or CM size is a good place to start.
For example, if you’re a CM 25 in an adidas, then reference the CM 25 row in the Nike sizing chart. And remember, when buying running shoes, add an extra centimeter over your actual foot size. The foot swells in volume during a run, so having a thumb’s width space ahead of the toe makes the fit comfortable.
Since not all identically-sized shoes share the same fit, here are some related guides on wide, narrow, and large-sized shoes.
Best running shoes in large sizes 14 to 20.
Best running shoes for narrow feet.
Best running shoes for wide feet.