It varies quite considerably. You need to take into account factors such as ab development, how body fat is distributed around your body, and how you measure it.

As a general rule, at 10 to 12% you’ll have fairly visible abs and be leaner than most.

At 8 to 10% you should have a six pack, 6 to 8% you’ll be on the cover of Men’s Fitness and 4 to 6% you’ll be in natural bodybuilding competitions.