The Short Answer
In US sizes, Nike and Adidas agree. Both charts put a US 9 on a 27.0 cm foot, so a Nike 9 is an Adidas 9. Most of the running brands agree with them: of our 139 charts, 115 put a US 9 at exactly 27.0 cm.
Two things do change. The EU label changes between those same brands, and your US size changes the moment you leave the running aisle.
One 27.0 cm foot → Nike 9 · Adidas 9 · Red Wing 10½ · Clarks 8½
Same foot. The sneaker brands agree; the boot and the dress shoe are two sizes apart.
Men's Size Comparison (Real Manufacturer Data)
| Foot (cm) | Nike US | Nike EU | Adidas US | Adidas EU | Difference |
|---|---|---|---|---|---|
| 25.5 | 7.5 | 40.5 | 7.5 | 40.7 | +0.2 EU |
| 26.0 | 8 | 41 | 8 | 41.3 | +0.3 EU |
| 26.5 | 8.5 | 42 | 8.5 | 42 | Same |
| 27.0 | 9 | 42.5 | 9 | 42.7 | +0.2 EU |
| 27.5 | 9.5 | 43 | 9.5 | 43.3 | +0.3 EU |
| 28.0 | 10 | 44 | 10 | 44 | Same |
Source: the men's size charts Nike and Adidas publish, as loaded in FitScan's brand database — the same table the widget reads.
Key insight: the US column is identical the whole way down, and the EU column is not. Adidas has no EU 42.5 at all — its ladder runs 42, 42.7, 43.3 — so a shopper reading "42.5" off a Nike box has nothing to match it to. At EU 42 itself the two agree exactly: both mean a 26.5 cm foot.
Don't guess — check
Enter your foot length and see your exact size in Nike, Adidas and 139 brands in total.
Compare My Sizes →Why the Difference?
- Different "last" shape — Nike tends to be narrower, Adidas slightly wider in the midfoot
- EU sizing is not standardized — there is no international law that says "EU 42 = X mm." Each brand decides.
- Rounding differences — Nike rounds EU to .5 (42, 42.5, 43), Adidas uses .3/.7 (42, 42.7, 43.3)
What About Other Brands?
Here the interesting part is not where brands differ, but how few of them do. These seven all sit on the same rung:
| Brand | US 9 Means | EU Equivalent | Width Tendency |
|---|---|---|---|
| Nike | 27.0 cm | EU 42.5 | Standard, narrow toe box on some models |
| Adidas | 27.0 cm | EU 42.7 | Standard to slightly narrow |
| Hoka | 27.0 cm | EU 42.7 | Wide toe box, narrow heel |
| ASICS | 27.0 cm | EU 42.5 | True to size |
| Brooks | 27.0 cm | EU 42.5 | True to size, wide options |
| Puma | 27.0 cm | EU 42.5 | Runs narrow, especially RS-X |
The Brands Where Your Number Really Changes
23 of our 139 charts put a US 9 somewhere other than 27.0 cm, and the spread between the extremes is 22 mm — about two and a half US sizes on one number. These are the ones that cost you a return:
| Brand | US 9 Means | vs the 27.0 cm consensus | Your size if you wear a Nike 9 |
|---|---|---|---|
| Red Wing | 25.5 cm | −15 mm | US 10½ |
| New Balance | 26.5 cm | −5 mm | US 9½ |
| Clarks | 27.5 cm | +5 mm | US 8½ |
| Ecco | 27.5 cm | +5 mm | US 8½ |
| Blundstone | 27.5 cm | +5 mm | US 8½ |
| Pikolinos | 27.7 cm | +7 mm | US 8½ |
Every figure above is read straight out of the size chart the brand publishes, and out of the same lookup the widget uses.
The Real Problem for Online Shoppers
Online footwear return rates run about 19% (median, UK 2026; 25–30% at large multi-brand retailers), and size or fit is the leading reason — up to 93% of footwear returns in one 2026 UK survey. That's not because people are careless — it's because sizing is inconsistent and confusing.
The solution: measure once, and let the chart answer. FitScan stores your foot measurement and reads each brand's own published chart — which matters least between Nike and Adidas, and most between a sneaker and a boot.
Your Size Passport
One measurement. Sizes in 139 brands. Free, instant, no signup required.
Get My Size Passport →FAQ
Q: Is Nike sizing the same as Adidas?
A: In US sizes, yes — a Nike 9 and an Adidas 9 are both a 27.0 cm foot. In EU sizes, no: the same foot is a Nike 42.5 and an Adidas 42.7, because the two ladders have different rungs. Width differs too.
Q: Should I size up in Nike?
A: If you have wider feet, yes — Nike runs slightly narrow. If you're between sizes, go up. See full Nike size chart.
Q: I wear Adidas EU 42. What's my Nike size?
A: Adidas EU 42 = 26.5 cm foot. For Nike at 26.5 cm, that's also EU 42 (US 8.5). In this case they happen to match, but at other sizes they diverge. Check your exact conversion.