Penis size is of interest to most men at some point in their lives. Whilst many experts insist that it is of little importance, there is little doubt that size can have a significant impact upon levels of self-esteem and confidence. So, how does your knob measure up? Get out your tape measure or ruler, measure your penis (erect size please!) along the top and enter your size below. Click the vote button and you'll see how your size compares with others in the web's biggest ongoing size survey!