MEN'S SHOES CONVERSION
Men's Shoes
Size
Men NIKE
6.5D
7D
8D
8.5D 9D 10D 11D 12D 13D
These sneakers
6D
6.5D
7D
8D
8.5D
9D
10D
11D
12D
Boots in store
6D
6.5D
7D
8D
8.5D
9D
10D
11D
12D

Measuring Guide 

For example:NIKE (size: 9D) = These sneakers (size: 8.5D) 

Always remember that the length of the shoe has little bearing on the fit. The fit across the foot is the key as this is what holds the foot in place. When trying shoes on always feel where the ball of the foot is located in the shoe as this is the part of the forefoot that makes contact with the floor first and wearing a shoe that fits correctly will prolong the life of the shoe.