Men who worry about their penis size are likely to have their fears eased by a new study designed to show them exactly where they stand on the issue.

When it comes to the size of their male member, most men are perfectly normal. Yet many men have their doubts, so David Veale, a psychiatrist and lecturer at King's College London, undertook a study to reassure them.

He and his colleagues reviewed 20 published studies that included measurements of over 15,000 men. Using this trove of data, the researchers constructed a nomogram, a graph that shows where each size ranks in a fashion similar to the way the distribution of SAT scores are laid out: Everyone's score is given a percentile ranking, with the 50th percentile being average — exactly in the middle.

Be forewarned that the graphs give sizes in centimeters, not inches, so you may want to bring along a calculator. One inch is 2.54 centimeters.

But unlike SAT scores, the graph revealed that there's very little difference between being in the bottom quarter and the top quarter when it comes to penis size.

According to the team’s analysis, the average flaccid penis is 9.16 cm (3.61 inches) long and the average erect penis is 13.12 cm (5.16 inches) long. Men in the 25th percentile averaged 3.2 inches, while those in the 75th percentile averaged 4.1 inches. That's a difference of less than an inch.

And the differences are just as minor when penises are erect. Being hung like a horse is the stuff of fantasies. Circumference (girth) averaged 3.67 inches flaccid and 4.59 inches when erect.

Men who still find all this emphasis on size distressing can take comfort in an earlier study which found that while only 55% of men were satisfied with their penis size, 85% of women were perfectly happy with the size of their partner's member. At least that's what they said. And what good is a relationship without some trust in it?

Men who'd like more details on just how they stack up can read Dr. Veale's article in BJU International. Be forewarned that the graphs give sizes in centimeters, not inches, so you may want to bring along a calculator or use one online. One inch is 2.54 centimeters.