How tight should MTB clipless shoes fit?

MTB clipless shoes should fit snugly without pressure points. You should be able to wiggle your toes slightly, and there should be no heel lift when you walk or simulate an upstroke. The shoe should feel like a firm handshake around your foot—not crushing, but with no slop. Remember that feet swell during riding, so a shoe that feels perfect at minute zero should have a tiny bit of room for expansion. If you feel numbness or hot spots within the first hour, the shoe is too tight or too narrow.