I have a pair of Genius 4's in a 42 that fit with tons of room and a pair of Dragon's that I ordered in a 42 based on the G4's. They fit, but man, they're tight. When I got my wife a pair of Dominator's in a half size I understood. The heel mold on her's said 39 and then there was a sticker that said "1/2". So, I'm pretty sure that my G4's are really a 42.5. Luckily these fit, but I'm ordering a new pair of Dom's for winter and will get a 42.5. I'd like the agree with the comments about trying a bunch of sizes on, but the shop my wife works for doesn't carry many different sizes, there just isn't a market for them here. EP though, rocks.