NMD R1 vs Ultraboost

Both are Adidas models but they fit differently: Ultraboost runs about 0.5 size s larger than NMD R1 at the same labelled US size.

At US men's 9 on NMD R1

If you wear NMD R1 in US 9, start with Ultraboost in US 8.5: go down 0.5 US sizes. The calculation keeps the same foot length anchor, about 262mm, then removes the NMD R1 fit offset (+0) and applies the Ultraboost fit offset (+0.25).

Model Recommended US Foot mm UK EU CM
NMD R1 9 262 8 39 26
Ultraboost (equivalent) 8.5 262 8 39 26

NMD R1 guide · Ultraboost guide