When I'm 100% rock hard, I am like 6 1/4", maybe 6 1/2" at best. When I have enough blood down there to consider it an "erection" though (not to be confused with a "semi"), it's like 5 1/2". Basically it's the kind of erection you get when it's in your pants and you don't want it, lol. It's softer and stouter looking than my rock-hard boner but I could still have sex with it if it could not get harder. I'm very happy that I have a healthy penis to where I get an erection almost instantly and remain rock-hard.