Adidas vs Nike Shoe Size - Which Runs Smaller?

Adidas runs about half a US size large compared to Nike. If you wear Adidas in US 9, start by checking Nike in US 9.5. Both brands use the same foot-length measurement; the difference is in the last shape, not the conversion formula.

Adidas to Nike size chart

Starting Nike size to check when you wear Adidas in each US men size.
US Men (Adidas) Adidas -> Nike Foot length
7 7.5 246mm
8 8.5 254mm
9 9.5 262mm
10 10.5 271mm
11 11.5 279mm

Fit verdict

  • Adidas: True to size (70% of buyers)
  • Nike: Runs small (55% of buyers)

Why the sizes differ

Adidas runs about half a US size large compared to Nike, with roughly 4mm between the matched fit records.

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