Luvons are available in whole sizes (6 - 11) and standard medium width.  They are generally true-to-size (everybody's feet are different!).

If you wear a half-size, we recommend sizing up if you wear wide width or prefer a looser fit. However, if you have narrow feet or prefer a snugger fit, we suggest sizing down.

US 6 7 8 9 10 11
UK 4.5 5.5 6.5 7.5 8.5 9.5
EU 36.5 37.5 38.5 39.5 40.5 41.5
JP 23 24 25 26 27 28