Studies On Penis Size
While results vary slightly across reputable studies, the consensus is that the mean human penis is in the range 12.9–15 cm (5.1–5.9 in) in length with a 95% confidence interval of (10.7 cm, 19.1 cm) or, equivalently (4.23 in to 7.53 in) — that is, it is 95% certain that the true mean is at least 10.7 cm but not more than 19.3 cm.
Another reputable source claims that the relaxed (flaccid, non-tumescent) human penis has an average length of only 4 inches (10 cm) and a diameter of 1.25 inches (3.2 cm) (which would result in a circumference of roughly 3.9 inches (9.9 cm)) while fully erect ones have an average length of 6 inches (15 cm) and a diameter of 1.5 inches (3.8 cm), resulting in an erect circumference of 4.71 inches (12.0 cm).
One study found the mean flaccid penis length to be 3.5 inches (8.9 cm). A review of several studies found average flaccid length to be 9–10 cm (3.5–3.9 in). Length of the flaccid penis does not necessarily correspond to length of the erect penis; some smaller flaccid penises grow much longer, while some larger flaccid penises grow comparatively less.
A study published in March, 2015, that measured 15,552 men across the globe from all races showed average flaccid size to be 3.6″ (9.16cm), with a girth of 3.7 inches (9.31cm).
The penis and scrotum can contract involuntarily in reaction to cold temperatures or nervousness, referred to by the slang term “shrinkage”, due to action by the cremaster muscle. The same phenomenon affects cyclist and exercise bike users, with prolonged pressure on the perineum from the saddle and the straining of the exercise causing the penis and scrotum to contract involuntarily. An incorrect saddle may ultimately cause erectile dysfunction (see crotch pressure for more information).
Several scientific studies have been performed on the erect length of the adult penis. Studies which have relied on self-measurement, including those from Internet surveys, consistently reported a higher average length than those which used medical or scientific methods to obtain measurements.
The following staff-measured studies are each composed of different subgroups of the human population (i.e. specific age range and/or race; selection of those with sexual medical concerns or self-selection) which could cause a sample bias.
In a study of eighty healthy males published in the September 1996 Journal of Urology an average erect penis length of 12.9 cm (5.1 in) was measured The purpose of the study was to “provide guidelines of penile length and circumference to assist in counselling patients considering penile augmentation.” Erection was pharmacologically induced in 80 physically normal American men (varying ethnicity, average age 54). It was concluded: “Neither patient age, nor size of the flaccid penis, accurately predicted erectile length.”
A study published in the December 2000 International Journal of Impotence Research found that average erect penis length in 50 Jewish Caucasian males was 13.6 cm (5.4 in) (measured by staff). Quote: “The aim of this prospective study was to identify clinical and engineering parameters of the flaccid penis for prediction of penile size during erection.” Erection was pharmacologically induced in 50 Jewish Caucasian patients who had been evaluated for erectile dysfunction (average age 47±14y). Patients with penis abnormalities or whose ED could be attributed to more than one psychological origin were omitted from the study.
A review published in the 2007 issue of BJU International showed the average erect penis length to be 14–16 cm (5.5–6.3 in) and girth to be 12–13 cm (4.7–5.1 in). The paper compared results of twelve studies conducted on different populations in several countries. Various methods of measurements were included in the review.
An Italian study of about 3,300 men concluded that stretched length was measured on average to about 12.5 centimetres (4.9 in). In addition, they also checked for correlations in a random subset of the sample consisting of 325 men.
A study published in March, 2015, that measured 15,552 men across the globe from all races showed average erect length to be 5.16″ (13.12cm0, and a girth of 4.6 inches (11.66cm), when erect.Source:
- Wessells, H.; Lue, T. F.; McAninch, J. W. (1996). “Penile length in the flaccid and erect states: Guidelines for penile augmentation”. The Journal of urology 156 (3): 995–997.
- Chen, J.; Gefen, A.; Greenstein, A.; Matzkin, H.; Elad, D. (2000). “Predicting penile size during erection”. International Journal of Impotence Research 12 (6): 328–333.
- “ANSELL RESEARCH – The Penis Size Survey”. Ansell. March 2001. Retrieved 2006-07-13.
Veale, D., Miles, S., Bramley, S., Muir, G. and Hodsoll, J. (2015), Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15 521 men. BJU International. doi: 10.1111/bju.13010
Do Black men really have larger penises than other races?
There are extremes in size across every race — extremely short penises, called micro penises, and extremely long ones. However, there’s no reputable modern research done into determining if black men are larger than other ethnic races. Most of what’s reported is anecdotal, and prone to exaggeration.
In the USA where African descendent men have largely cross-bred with Caucasian races, the average size of black men is actually the same as the white population. But the stereotype persists about black men having big penises in the USA, and black men from the USA have embraced it even though it has no actual basis in fact. There will always be extremes of size in any race of men, and it is often these examples we see in pornography that are presented as being the average black man.
The problem with this fallacy is it places black men who are average by the general standard (5″-6.5″) in a position where they are suffering small penis syndrome because they think 7″-8″ is supposed to be average. This kind of misinformation is having a very negative effect on these men. One of the many negative effects porn has on the psyche of the average man.
Tables and maps you might find on the web showing the distribution of penis size across the globe are completely bogus, made up by people who want to spread misconceptions (usually to make money from men’s anxieties over penis size). So never take any information on face value unless you can verify that the source is reputable.
Can Penises shrink?
Weight gain is a common cause of making the penis seem smaller. We cover this aspect of shrinkage on our Obesity Page.
The human penis does undergo an actual (and irreversible) reduction in size as men age. The reduction — in both length and thickness — typically isn’t dramatic, but may be noticeable. A man may shrink up to half an inch by the time he’s seventy to eighty-years-old, compared to his size in his twenties. Shrinkage amount does vary per individual, but rest assured it’s never significant shrinkage (i.e. Shrinking more than half an inch is not going to happen).
What causes the penis to shrink?
At least two mechanisms are involved. One is the slow deposit of fatty substances (plaques) inside tiny arteries in the penis, which impairs blood flow to the organ. This process, known as atherosclerosis, is the same one that contributes to blockages inside the coronary arteries – a leading cause of heart attack.
The other mechanism involves the gradual build up of relatively inelastic collagen (scar tissue) within the stretchy fibrous sheath that surrounds the erection chambers. Erections occur when these chambers fill with blood. Blockages within the penile arteries – and increasingly inelastic chambers – mean smaller erections.
As penis size changes, so does the size of the testicles. Starting around age forty, the testicles definitely begin to shrink. The testicles of a thirty-year-old man might measure one to one and a half inches in diameter, but a seventy-year-old man’s testicles are often just under an inch in diameter.
If there’s a silver lining to these presumably unwelcome changes, it’s this: Research has found these changes need not ruin your sex life. One recent study involving 2,213 men in Olmstead County, Minn., showed significant declines in erectile function, libido, and ejaculatory function, but only moderate decreases in levels of sexual satisfaction. “Older men may be less likely to perceive these declines as a problem and be dissatisfied,” concluded the studies authors.
I think my penis is smaller than average.
Most men think they are smaller than average. They get this view from looking down on their flaccid penis in locker rooms, or from watching porn films where well endowed studs thrust away endlessly on the moaning female “stars” until they explode in a volcanic crescendo.
The truth is that if you look down at your genitals from the top in a locker room, or anywhere else for that matter, you are going to get a shortened view of your penis: to appreciate its true size, you need to see it sideways on in a mirror. It then suddenly looks longer! And if you watch porn films, you’re not seeing average sized men – you’re seeing a small number of men who have penises so large that they are in demand to appear in porn films. And, by the way, the reason they go on for so long during sex is that they are totally detached from their feelings, not seeing the women as people, but as sex objects, and they are also cut off from the process of arousal and excitement that makes sex so enjoyable for most of us. They also stop and start for different positions, then it’s edited to look like one long continuous fuck and suck. It may come as a surprise that a man can have a rock hard penis and not be aroused – but that’s one of the mysteries of male sexuality.
Women like a man with a big penis.
No, they don’t. A few women may like being stretched to the limit, or poked in the cervix during sex, but most do not care about the size of their man’s penis. The problem here is the male thinking that “bigger equals better.” This logic is based on the way men get sexual pleasure: the more friction, the better the sex. Therefore, a man may think that an above-average penis is going to give a woman more sensation. It seems like a logical connection. But women are not looking for physical sensation like this during sex. They are looking for emotional connection, a feeling of being loved, a sense of being special and cherished, and closeness and intimacy with their partner.
And what’s the proof of this? Look on the women’s “community” message boards on the internet and in general you won’t find size discussed as an issue. It’s the men’s advice boards and websites that focus on penis measurement and comparison! Try it yourself if you want, by searching for “what women think about the penis” in Google or Yahoo. What you’ll get is a plethora of get-bigger-quick sites telling you that size really, really does matter, and a few sensible websites aimed at men telling you that your penis is good for everything no matter how big or small it may be. But you won’t find female oriented websites discussing the issue very much. What does that tell you? That it’s just not an issue in women’s consciousness, perhaps?
Where women and penises are concerned, bigger is better for sex.
Actually, it isn’t. If anything, women prefer a thick penis to a long one. This research was done at an American college by asking fifty sexually active women what they preferred: and they said they preferred thickness to length. But although the results were statistically significant, they were not hugely so. It isn’t a matter of great importance to women.
Julia Bourland is a sex columnist for the San Francisco Chronicle and author of The Go-Girl Guide: Surviving Your 20s With Savvy, Soul, and Style. Here’s what she says in her advice for women:
In candid discussions with girlfriends, we’ve come to the unanimous conclusion that length is a far less critical component to the size factor than width. In fact, an extra long penis is even questionably desirable since its apt to penetrate too deeply and pain the delicate cervix. An extra short penis on the other hand is still able to reach one’s vital spot (the G-spot is just an inch or so back along the front wall of the vagina.) So if you’re the type to enjoy G-spot pleasure – and not all women are – then a short penis will do no wrong. Unless it’s short and thin. Then it may not have enough girth to trigger your arousal.
“If you are not satisfied by your partner’s size, you will want to get creative about your sex positions. A short, thin penis may feel more substantial while engaging in variations of doggy style, which allows for deeper penetration. Using different positions and alternating with a vibrator now and then may increase the pleasure for both of you since many men find that the most satisfying sex is that which arouses their partner. Two other aspects of good sex that men can control matter as well – friction and awareness. For many women the key erogenous zone, the clitoris, is rarely dependent on the penis for orgasmic release. If your mate has the right rhythm, a marathon level of endurance and a keen awareness of all of your erogenous zones, the pleasure will come – regardless of length or width.
My penis says it all about my masculinity – the bigger it is, the more manly I am
In all the years I’ve worked with men, I have never seen any evidence that masculinity is connected to genital size. I know that a sense of self-esteem might come through being able to walk around the locker room or the changing room with an enormous dick swinging in front of you – but that doesn’t mean you’re more of a man. It’s a social construct that penis size equals masculinity. The truth is this: the length and width of your penis has no relationship whatsoever to those masculine values worth cultivating – the ones that make you a real man: the ability to father a child, either biologically or socially, the strength of character to be a model citizen or a good leader, the personal depth to be a creative force both personally and in the community, and a powerful and emotionally aware male in your relationships, the dedication to be a mentor to adolescent boys, and the determination to think with power and clarity and get what you want out of life. If you had to choose between a big dick and those values, what would you choose? And, out of interest, which do you think would be more likely to attract women?
The bigger my penis, the better the sex.
Not at all. For one thing, some women have smaller vaginas than others, especially Asian women, and for another the intensity of your orgasm is related to how aroused you are, not your physical size. And you don’t last for longer during sex if you’re on the large size. Men who experience premature ejaculation come in all shapes and sizes. I know this because I have spent a long time counselling men with PE. The cure for premature ejaculation is greater self-confidence, a better relationship with your spouse or partner, eliminating fear and guilt from sexual relationships, and open and honest communication. It doesn’t lie in the size of your manhood, or falling for the line peddled by the “get-bigger-quick” sites about how you’ll be able to make love all night when you’re two inches longer. By the way, if you want to know how to deal with premature ejaculation, go here.
I can’t satisfy a woman unless I have a big dick.
No woman would ever agree with that. Only a minority of women orgasm through vaginal intercourse – and if they do, it’s because the penis is stimulating their G spot. (A penis in the vagina doesn’t stimulate the clitoris.) And guess where the G spot is found? About two-three inches inside the vagina on the upper wall. Now, is your penis two-three inches long? Yes? It is? Oh, good! So, if you want to, you can give a woman a vaginal orgasm. Most couples never realize this, because they don’t know how vaginal orgasms are produced. You can read about it here, or if you don’t want to bother, you and she can be quite satisfied with clitoral orgasms: these come from stimulating her clitoris with your tongue, your fingers, a vibrator, or the tip of your penis, rubbing outside her vagina on her vulva and clitoris. Here is an email on an internet discussion board from a woman:
My husband has an erect penis just under five inches, and it’s not thick. But I can assure you, he can absolutely drive me crazy with it – and for hours! I guess desire and technique are more necessary and appreciated for a small man? As you know, the clitoral area, the labia minora, and the vulva are delectably excitable. So, the smaller organ may be better able to stimulate that area. He teases me there with just the tip of his penis. WOW! Talk about multiple orgasms! So, if you’re a man who doesn’t have the largest of penises, please don’t feel too bad about it – you can still do it for a woman!
As far as the penis is concerned, size is more important than shape.
Well, you might think so, but did you ever ask a woman what she thinks? Here’s an extract from a women’s message board on the internet:
Did it ever occur to you that a penis shaped like a lollipop with a big knob and a thin shaft was exactly right for sucking, whereas one with a small, pointy helmet on a bigger shaft would ease the way in anal intercourse?
I have it admit it had never occurred to me either, but I do see the point. I guess the ideal penis varies depending on what you’re trying to do with it.
A woman who’s given birth won’t get pleasure from my penis during sex.
The last myth to see off is the old one about childbirth stretching the vagina. Women who’ve had children don’t normally have looser vaginas than women who’ve never given birth. It’s that amazing elastic quality of the vagina – it stretches to give birth, it recovers. In any event, if a woman who’s had a baby feels she might be a bit more stretched than before, she can always use Kegel exercises to tighten her muscle tone – and since that lets her positively grip her man’s penis, sex may feel better for both partners! But it’s not a matter of vaginal size – it’s more a matter of vaginal fitness.
More Sex Myths…
1. Men are more interested in casual sex than women
FALSE: Despite what sitcoms since the 1970s would have us believe, men are not all out to spread their seed on endless one-night stands. Professor Terri Conley from the University of Michigan recently reviewed an oft-cited 1989 study which supported the theory that men are more interested in casual sex. In that study researchers trained young men and women to proposition strangers for sex. They found 70 per cent of the men approached by a woman seeking sex saying, ‘sure’ while not a single woman agreed. Conley argued that there is evidence that cultural factors play a major role and context was needed. In her study, when men and women considered hypothetical offers of casual sex from famous people, or offers from close friends whom they were told were good in bed, the gender differences in acceptance of casual sex disappeared.
2. Men want to sleep with their friend’s wives
FALSE: If you’re worried about adultery within your friendship circle this new research may ease your concerns. A recent study (2012) from University of Missouri found that male testosterone levels drop when interacting with the spouse of a close friend. Why there may be ample opportunity due to time spent together, researchers believe it might be an evolutionary aversion.
“Men’s testosterone levels generally increase when they are interacting with a potential sexual partner,” said Mark Flinn, professor of anthropology at the university.
“However, our findings suggest that men’s minds have evolved to foster a situation where the stable pair bonds of friends are respected.”
3. Men have more sex partners than women
FALSE: According to a study published in the February (2013) edition of the Journal of Personality and Social Psychology, men and women have more or less the same amount of sex across their lifespan. While there are differences in sexual interest over a lifespan, the variation was highest between individuals, not between sexes. And while studies generally find men reporting more sexual partners than women, there seems to be some fibs being told. In 2003, researchers reported in the Journal of Sex Research that if you trick participants into believing that they are hooked up to a lie-detector test, women actually report the same number of sexual partners as men, with women more likely than men to have different answers depending on conditions under being surveyed.
4. Headaches and sex don’t mix
FALSE: That old ‘not tonight love, I have a headache’ excuse might not work as well as expected when your partner explains that, according to a recent study (2012), they know just the cure. Research from the University of Munster in Germany found that having sex may actually be more effective in curing a headache than painkillers due to the endorphins triggered. They found that more than half of migraine sufferers in the study who had sex during a migraine experienced an improvement in symptoms, though for a third of the responding patients, sex worsened the migraines.
5. Sex is a great workout
FALSE: It seems getting horizontal doesn’t have the added benefit of being the workout we once believed. A recent study published in the New England Journal of Medicine (2012) debunked the commonly held notion after finding that on average a 6-minute romp (the average time they found sex to last) would only burn 88 kilojoules (21 calories). This is well under the inflammatory claims in the past of up to 1255 kilojoules (300 calories) burnt per encounter. You could burn those same 88 kilojoules by taking a 4-minute brisk walk around the block followed by a cold shower.