Adidas vs Brooks Shoe Size — Which Runs Smaller?
Adidas and Brooks run true to each other — keep your usual size as the starting point when switching. If you wear Adidas in US 9, start by checking Brooks in US 8.5. Both brands use the same foot-length measurement; the small differences are in last shape, not the conversion formula.
Save this comparison profile
Save your usual Adidas size, then reuse it across brand comparisons without retyping.
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Switching rule for this pair
At the US 9 anchor, the same 262mm foot maps to Brooks US 8.5. In plain terms: when moving from Adidas to Brooks, go down half a US size.
- Adidas: true to size signal from 70% of buyer-fit data.
- Brooks: true to size signal from 65% of buyer-fit data.
- If you know your foot length in millimetres, use the Size Passport above before trusting a label-to-label switch.
Adidas → Brooks size chart
| US Men (Adidas) | Adidas → Brooks | Foot length |
|---|---|---|
| 7 | 6.5 | 246mm |
| 8 | 7.5 | 254mm |
| 9 | 8.5 | 262mm |
| 10 | 9.5 | 271mm |
| 11 | 10.5 | 279mm |
Fit verdict
- Adidas: True to size (70% of buyers)
- Brooks: True to size (65% of buyers)
Why the sizes differ
Adidas and Brooks run about the same size.
Adidas foot length is measured in millimetres, then mapped to US size. The Brooks last fits the same foot, but the starting label stays the same because of each brand's fit bias — not a different conversion formula.