Brooks vs ASICS Shoe Size - Which Runs Smaller?
Brooks runs about half a US size large compared to ASICS. If you wear Brooks in US 9, start by checking ASICS in US 9.5. Both brands use the same foot-length measurement; the difference is in the last shape, not the conversion formula.
Brooks to ASICS size chart
| US Men (Brooks) | Brooks -> ASICS | Foot length |
|---|---|---|
| 7 | 7.5 | 246mm |
| 8 | 8.5 | 254mm |
| 9 | 9.5 | 262mm |
| 10 | 10.5 | 271mm |
| 11 | 11.5 | 279mm |
Fit verdict
- Brooks: True to size (65% of buyers)
- ASICS: True to size (75% of buyers)
Why the sizes differ
Brooks runs about half a US size large compared to ASICS, with roughly 2mm between the matched fit records.
Brooks foot length is measured in millimetres, then mapped to US size. The ASICS starting size shifts by about half a US size because of each brand fit bias, not a different conversion formula.