A lot of people recommend going up a half, or even full size, for Inov8 shoes. But not everybody. FWIW, I wear a size 12.5 in everything - Inov8, Altra, Vibram FF, Hanwag, Adidas and so on. I do not feel like these are short, but it is probably that they are narrower than what people prefer or are used to, so they size up. A narrower toe box usually leads to more accurate footing on technical terrain and climbing.