Nike vs Brooks Shoe Size - Which Runs Smaller?

Nike runs about half a US size small compared to Brooks. If you wear Nike in US 9, start by checking Brooks in US 8. Both brands use the same foot-length measurement; the difference is in the last shape, not the conversion formula.

Nike to Brooks size chart

Starting Brooks size to check when you wear Nike in each US men size.
US Men (Nike) Nike -> Brooks Foot length
7 6 246mm
8 7 254mm
9 8 262mm
10 9 271mm
11 10 279mm

Fit verdict

  • Nike: Runs small (55% of buyers)
  • Brooks: True to size (65% of buyers)

Why the sizes differ

Nike runs about half a US size small compared to Brooks, with roughly 6mm between the matched fit records.

Nike foot length is measured in millimetres, then mapped to US size. The Brooks starting size shifts by about half a US size because of each brand fit bias, not a different conversion formula.