However, it seems that both men and women think the average penis is bigger than it really is. Although we can’t say with certainty what the average penis size is, the most definitive data we have comes from a recent review paper published in the British Journal of Urology International in which scientists looked at the results of 20 studies that included measurements of 15,521 penises from around the world.

In this sample, the median (50th percentile) penis length was 13.1 cm (5.2 in). This is a little shorter than the average guess in the DrEd survey, but still reasonably close.

However, it’s quite a bit shorter than what people say the ideal penis size is. In the DrEd survey, women rated the ideal penis length as 15.8 cm (6.2 in), while men rated the ideal penis length as 16.6 cm (6.5 in).

Given the sizable gap between perceived average and ideal penis length, it is probably not surprising to see that many men in the DrEd survey reported being dissatisfied with their penis size and, further, that their penis size had a negative effect on their sexual confidence.

Interestingly, there was quite a bit of variability across countries when it came to estimates of perceived average penis length and ideal penis length. The relative difference between these numbers varied a bit, too.

As you can see in the figure below, average perceived penis length was longest in Poland and Austria, but shortest in France and the U.K, with the U.S. coming in toward the middle.