Many scientific research papers have tried to answer the question to which many men want an answer - what is the average penis size?
The published findings are often introduced with background information on men's widespread anxiety about whether or not their penis is big enough, and if sexual partners are going to be satisfied. So what is the truth?
The truth about male genital length and girth might have become obscured by the free and widespread availability of internet pornography.
Perhaps it is no surprise that researchers say men have heightened anxieties about their manhoods. And another aggressive industry pushes dubious promises of a bigger penis through enlargers and extenders.
Unfounded worries about inadequacy are not helped by the fact that a man's own view of his penis automatically makes it look smaller to him than to someone else. This is simply because looking down at the penis from above makes it appear smaller, compared with how it looks straight on, or from the side.
Seeing one's own penis from this unreliable point of view, and comparing it with other men's appendages from a different view, may reinforce false ideas of penis size.
Fast facts on the average penis size
Here are some key points about the average penis size. More detail and supporting information is in the main article.
- While 85% of women were satisfied with the size and proportion of their partner's penis in a study, men were less sure of themselves.1
- 45% of men in the study believed they had a small penis.
- Across studies it has been concluded that flaccid lengths range around 7 to 10 centimeters (2.8-3.9 inches).
- Flaccid circumferences range around 9 to 10 centimeters (3.5 to 3.9 inches).
- Erect lengths range around 12 to 16 centimeters (4.7 to 6.3 inches).
- Erect circumference (only one previous study) was around 12 centimeters (4.7 inches).
Women seem to care less about penis size than men
Male concern about whether penile size lives up to the desires of females seems to be largely misplaced.
One study, published in the British Journal of Urology International, suggested that while the majority of women, some 85%, were satisfied with the size and proportion of their partner's penis, men were less sure of themselves.1
Almost half of men in the study (45%) believed they had a small willy - yet the researchers reported that small penis size was actually rare.Some 170 women answered questionnaires in another study, which found that while they attached some importance to penis size, it was only of "substantial" importance to a "clear minority" of the women.2
While most of men's worries about penis size centre on the length, women are more interested in width, according to one study.3
The study of 50 sexually active undergraduate women reported that penis width was more important to sexual satisfaction than penis length.
When is penis size too small?
Perhaps the best gauge of what is considered to be a small penis is given by the threshold used by doctors for when penile augmentation may be considered.
Researchers publishing in the Journal of Urology studied the penis sizes of 80 "physically normal" men, measuring penile dimensions before and after drug-induced erections. After finding average sizes, they concluded:4
"Only men with a flaccid length of less than 4 centimeters [1.6 inches], or an erect length of less than 7.5 centimeters [3 inches] should be considered candidates for penile lengthening."
Male sexual dysfunction
Not being able to have penetrative sex may be more worrying than size. Sexual performance can be affected by erection and ejaculation problems.
What is 'normal' or average penis size?
That last study determining the threshold for a small member is one of a number that have measured the penis sizes among groups of men, and worked out an average.4
The mean average length for the penises came to:
- 8.8 centimeters (3.5 inches) for the flaccid length
- 12.9 centimeters (5.1 inches) at the erect length.
The study also found that the size of a man's erect penis was not correlated with the size of his flaccid penis - in other words, men with different lengths of floppy penis may have similarly sized willies when hard.
This finding has been supported by a study of 200 Turkish men, in which "flaccid length had little importance in determining erect penile length."5
You can see from this anatomical diagram that the penis extends back behind the testes - measured lengths do not include this part.
The research to determine average penis size includes a recent study, published in January 2014.6
It examined over 1,600 American men, although it did not take independent physical measurements, and instead relied on the men's own measurements of penis size. The reports were probably fairly reliable, however, since the men would then be given condom sizes to match what they said, so that any inaccuracy would have resulted in prophylactics that were baggy or tight.
The study found an average penis size as follows:
- Erect penile length of 14.2 centimeters (5.6 inches)
- Erect penile circumference of 12.2 centimeters (4.8 inches).
The researchers said the self-reported erect penile dimensions were consistent with findings from other studies. Their study added the finding that the precise dimensions of an erection can be influenced by the "mode" of getting aroused - such as whether a man uses "hand stimulation."
On the next page we look at average penis size measurements from studies and we discuss the idea of penile enlargement procedures.