Many scientific researchers have tried to answer the question men (and women) worldwide want clear information about - what is the average penis size?
We will present you with facts from all the scientific studies done on penis size so that once you have finished reading this article, you will feel content that you have the most accurate answer to the question. And perhaps you will be reassured about your own size or that of your partner's penis.
Published findings are often introduced with background information on men's widespread anxieties about whether or not their penises are big enough, and if sexual partners are going to be satisfied. So what is the truth?
Given the ubiquity of free, easily accessible internet pornography, and the rise in aggressive marketing by companies promising a bigger penis through the use of extenders and enlargers, it is easy to see why the truth about male genital length and girth might have become obscured.
Perhaps it is no surprise, then, that researchers consistently find that men have heightened anxieties about their manhoods.
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 may be satisfied with the size and proportion of their partner's penis, men are less sure of themselves.
- As much as 45% of men believe they have a small penis.
- Across studies, flaccid length average from 7 to 10 centimeters (2.8 to 3.9 inches).
- Flaccid circumference/girth average from 9 to 10 centimeters (3.5 to 3.9 inches).
- Erect lengths average from 12 to 16 centimeters (4.7 to 6.3 inches).
- Erect circumference is around 12 centimeters (4.7 inches).
When is penis size too small?1
The penis extends back behind the testes - measured lengths do not include this part.
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:
"Only men with a flaccid length of less than 4 centimeters [1.6 inches], or a stretched or erect length of less than 7.5 centimeters [3 inches] should be considered candidates for penile lengthening."
What is 'normal' or average penis size?1-3
In the Journal of Urology study, researchers found the following among the group of 80 men:
- An average penis size of 8.8 cm (3.5 inches) when flaccid
- An average penis size of 12.9 cm (5.1 inches) when erect.
Many studies have investigated average penis size.
The study also found that the size of a man's erect penis was not correlated with the size of his flaccid penis, meaning that men whose penises are different lengths when flaccid may have similarly sized erect penises. There was also no relationship between the men's ages and their penis sizes.
The finding on how much the penis length can 'grow' - on whether you are a 'shower' or a 'grower' - was further supported by a study of 200 Turkish men, in which "flaccid length had little importance in determining erect penile length."
The research to determine average penis size includes a study published in January 2014 that examined over 1,600 American men, although it did not take independent physical measurements.
Instead the study relied on the men's own measurements of penis size. The reports may be considered fairly reliable, however, since the men were to be given condoms to match their self-reported measurements, meaning that any inaccuracy would have resulted in ill-fitting prophylactics.
This study found the average penis size to be as follows:
- Average size for an erect penis is 14.2 cm (5.6 inches)
- Average circumference of an erect penis is 12.2 cm (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.
Several different studies have suggested an average penis size of between 5.1 and 5.6 inches.
Penis size - women seem to care less about it than men4-6
Male concern about whether penile size lives up to the desires of females seems to be largely misplaced. And 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.
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 perspective and perhaps comparing it with other men's appendages from a different perspective, may, therefore, reinforce false ideas of penis size. But do women have a more reliable perception?
Male sexual dysfunction
Not being able to have penetrative sex may be more worrying than penis size. Sexual performance can be affected by erection and ejaculation problems.
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.
Almost half of men in the study (45%) believed they had a small penis - 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.
While most of men's worries about penis size centre on the length, women are more interested in width, according to one study.
The study of 50 sexually active undergraduate women reported that penis width was more important to sexual satisfaction than penis length - for a big majority, for 45 of the women.
Women don't want men with big penises7
A study published in the open-access journal PLOS ONE in November 2015 took the novel approach of asking women to show their penis size preferences with the use of 3D printed models of 33 different dimensions.
The women were asked to choose between 33 differently sized 3D-printed 'penises' - including the examples shown. The largest in the set was A, while D was the smallest; they were blue for racial neutrality.
Image: Nicole Prause et al.
The sizes had been printed across a range from 4 inches to 8.5 inches in length, and from 2.5 inches to 7.0 inches in circumference - based on previous studies giving an average American penis size when erect of 6 inches (15.2 cm) long with a girth of 5 inches (12.7 cm).
The 3D-printed shafts were in blue plastic so as not to suggest any particular race that might prejudice the women's ideas of average size.
The 75 women indicating size preferences from the 33 blue models chose slightly differently depending on the kind of relationship they were thinking about (and in any case showed they desired a length that turned out to be only slightly above the averages found across studies):
- For long-term sexual partners they went for a penis of slightly shorter circumference and length compared with their choices for one-night stands - choosing an average length of 6.3 inches and a girth of 4.8 inches
- This compared with their preference for one-time sex partners being for a length of 6.4 inches and a circumference of 5.0 inches.
Follow us to the next page where we look at more results from studies about penis size and discuss concerns about age, obesity and penis enlargement.