Adidas vs ASICS Shoe Size - Which Runs Smaller?

Adidas and ASICS run true to each other. Keep your usual size when switching. If you wear Adidas in US 9, start by checking ASICS in US 9. Both brands use the same foot-length measurement; the small differences are in last shape, not the conversion formula.

Adidas to ASICS size chart

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

Fit verdict

  • Adidas: True to size (70% of buyers)
  • ASICS: True to size (75% of buyers)

Why the sizes differ

Adidas and ASICS are close enough to treat as the same size at the brand level. The measured gap is about 0mm.

Adidas foot length is measured in millimetres, then mapped to US size. The ASICS starting size stays the same because of each brand fit bias, not a different conversion formula.