An international study of more than 15,000 penises has compiled all available data on penis length and girth to come up with the best average yet.

In an effort to assuage the anxiety of men who harbour deep concerns about their penis size, despite falling in the 'normal' range, researchers from King's College London in the UK took it upon themselves to come up with a more accurate average measurement for both flaccid and erect penises. The problem with previous estimates? They've often relied on self-reporting, and it's news to exactly no one that when it comes to penis size, self-reporting is the fastest way to Inaccurate Town.

"People tend to overestimate themselves," lead author and psychiatrist David Veale told David Shultz at Science. "[Men] seem to have a very distorted picture of what [size] other men are, and what they believe they should be."

"It still just strikes me how many men have questions and insecurities and concerns about their own penis size. We actually do need good data on it," Debra Herbenick, a behavioural scientist at Indiana University in the US, who was not involved in the study, told the AFP

So for their analysis, the team compiled data from 17 different academic papers on measurements taken by clinicians around the world of 15,521 men, according to standardised measuring procedures. This means measuring from the pubic bone to the tip of the tip of the distal glans, not counting any fat around the pubic area, or extra length provided by foreskin. Girth is measured either around the base, or around the middle. (Just in case you want to play along at home.)

Putting everything they found in one big graph, it became obvious where the outliers were, and where the average lay. 

According to the paper, published today in the British Journal of Urology International, the average flaccid penis measures 9.16 cm (3.61 inches) in length, while an average erect one will be 13.12 cm (5.16 inches) long. Girth, on the other hand, is 9.31 cm (3.66 inches) for the average flaccid penis and 11.66 cm (4.59 inches) for an average erect penis.

The outliers? "A 16-cm (6.3-inch) erect penis falls into the 95th percentile: Out of 100 men, only five would have a penis larger than 16 cm," the AFP reports. "Conversely, an erect penis measuring 10 cm (3.94 inches) falls into the 5th percentile: Only five out of 100 men would have a penis smaller than 10 cm."

While these new measurements might be good news to those men who now fit into the 'average' group, the team is careful to point out that those who don't still have very little to worry about. They conclude in the paper:

"[In] a large Internet survey of 52,031 heterosexual men and women, 85 percent of women were satisfied with their partner's penis size, but only 55 percent of the men were satisfied with their own penis size. Thus, only 15 percent of women say they that erect penis size is important and erect girth is generally more important than length. It is not known how many of the 15 percent of women were also partnered with a man who also believed he was too small. Such preferences may also be different in the homosexual community."

Oh and those questions about whether finger length, foot size, age, and so-on has an effect on your penis size? The team also scoured the scientific literature for connections there, and found the correlations to be either inconsistent or weak. So those of you with little shoes, wear them with pride - they don't mean a thing.

Sources: The Guardian, Science