USA MENS
4 5 6 6.5 7 8 9 10 11 12 13
EURO
36 37 38 39 40 41 42 43 44 45 46
UK
3 4 5 5.5 6 7 8 9 10 11 12
MM
235 240 250 252 255 260 270 275 285 290 295
CM
23.5 24.0 25.0 25.2 25.5 26.0 27.0 27.5 28.5 29.0 29.5

If you normally wear a ½ size, buy the next full size. For example, 10 ½, buy an 11.