The Average Penis Size Isn’t as Big as You Think

Annie Hayes
·13-min read

When was the last time you got a proper look at another man’s penis? We’re not talking about porn stars, who have quite literally made their manhood into a career and, let’s face it, hardly represent the nation’s equipment. We’re talking about IRL viewing, to get an idea of the average penis size.

On the few occasions you do glimpse another man’s member – in the changing rooms at the gym, for example – the angle is likely to be far more forgiving than your own bird’s-eye perspective. Little wonder most men have a pretty warped idea of what the ‘average penis size’ actually looks like.

If you’re under the impression that the average penis size is 6 inches in length when erect – and most men are, according to a study by Clemson University – prepare to have your entire world rocked. The true average is up to an inch smaller, the researchers revealed. A revelation for anyone overly-concerned with how their phallus stacks up.

“A man’s perception of his penile length can greatly affect his self-esteem,” says Vivek Wadhwa, consultant urological surgeon at Solihull’s Spire Parkway Hospital. “Most men presenting to their doctors concerned about inadequate penile size are within the normal range, functionally adequate for sexual activity and require reassurance.”

Translation? It’s (probably) all in your head. Here’s what the experts have to say about the relationship between average length and sexual satisfaction...

What Is the Average Penis Size?

The average penis size without an erection measures between 3 and 4 inches, and the average penis size with an erection is between 5 and 6 inches, states Abbas Kanani, pharmacist at Chemist Click. In terms of girth, you’re looking at an average circumference of around 3 to 4 inches when flaccid, and between 4 and 5 inches when erect.

Want a solid comparison? The biggest study to date, published in the journal BJU International, measured the members of 15,521 men across the globe. The average length of an erect penis is 13.12 cm (5.16 inches) and 11.66 cm (4.59 inches) in girth. When flaccid, the average length is 9.16 cm (3.6 inches) stretched, and the girth is 11.66 cm (4.59 inches)

Another review, which included studies from 16 countries – one of which dated back to 1899 – revealed similar measurements. Flaccid lengths ranged from 7 to 10 cm (2.8 to 3.9 inches), flaccid circumferences ranged from 9 to 10 cm (3.5 to 3.9 inches) and erect lengths ranged from 12 to 16 cm (4.7 to 6.3 inches).

Photo credit: Ilka & Franz - Getty Images
Photo credit: Ilka & Franz - Getty Images

Are any of these figures definitive? Far from it. As you’re likely well aware, both the length and girth can fluctuate depending on your surroundings and how stimulated you are. In fact, there are a whole host of factors that can alter your penis size. Here’s the long and short of it:

The Temperature

“In colder weather, a non-erect penis is usually smaller than usual,” Kanani explains, “because the blood vessels constrict in order to preserve warmth within your body. By the same token, hot weather can increase the size of the non-erect penis as blood vessels dilate and there is better blood flow around your whole body.”

Arousal Levels

If you’re especially in the mood, your member will totally show it. “It is also common to experience stronger erections that are slightly larger than usual when you are more stimulated than normal,” Kanani continues. “This is owed to the increased blood supply that your penis receives when you are feeling extra stimulated.”

Your Age

After the age of 40, burgeoning birthday candles can cause your penis to appear smaller, due to a combination of reduced testosterone and age-related circulatory conditions. One example is arteriosclerosis, where your arteries become clogged with fatty deposits. “If they occur in the arterial blood supply to the penis, this will result in your erections becoming less firm,” says Dr Deborah Lee, of Dr Fox Online Pharmacy.

The Shape

Whenever you injure your penis – during rough sex or sport – scar tissue forms. Over time, it can build up, causing your member to bend or curve when you have an erection, known as Peyronie’s disease. “It’s quite normal for an erect penis to deviate slightly to the left or right,” says Dr Lee. “However, if there is a marked curvature that would make vaginal penetration difficult or impossible, it may indicate Peyronie’s disease.”

Your Weight

Your manhood is attached to your abdominal wall, so as your belly expands, it appears to pull the penis inward. “As you gain weight, you may develop an abdominal fat pad – known as a pannus – which projects outwards and hangs over the genital regions,” says Dr Lee. “This means the penis may be hidden from a bird’s eye view and can look shorter as it emerges from underneath the fat pad.”

Erectile Dysfunction

The firmer the erection, the bigger your member. That’s a fact. “If you suffer from erectile dysfunction (ED), your penis will not be achieving its full length and girth,” says Dr Lee. “ED is very common, affecting 50 per cent of men over 50. It’s often due to psychological causes, including relationship problems, but it can signify heart disease or diabetes. If you have ED, see your GP without delay.”


Certain types of prescription drugs can cause your penis to appear smaller than it actually is. These include Adderall – due to “vasoconstriction in the penile blood vessels,” says Dr Lee – and certain antidepressants, which can “alter genital sensitivity, and reduce sexual function”.

Finasteride, which is used to treat hair loss and enlarged prostate in men, reduces your T-levels and can alter the structure of erectile tissue. Additionally, prostate surgery and prostate cancer treatment is also associated with penile shortening.


Yet another reason to lay off the cigs: smokers are up to twice as likely to develop erectile dysfunction as non-smokers. “Smoking has been shown to dampen the effects of sexual arousal,” says Dr Lee. “This may be due to the release of brain neurotransmitters, or due to the inhibitory effect on the release of nitric oxide in penile tissue.”

Wishful Thinking

Interestingly, sexually-active blokes have a tendency to overestimate the size of their member when self-reporting the measurements, a US study of college-age men found. This is likely because they have a “greater sense of masculinity, sexual competence, and prowess” than those who have no shared sexual experience, the authors speculated.

What Penis Size Is Too Small?

Micropenis is diagnosed when the length is at least 2.5 standard deviations below the average for your age bracket. Affecting just 0.14 per cent of the general population, this rare condition is determined at birth, and occurs due to hormonal or genetic abnormalities. When an average-sized penis appears almost hidden because of excess skin, it’s called a buried penis.

Photo credit: Larry Washburn - Getty Images
Photo credit: Larry Washburn - Getty Images

While both micropenis and buried penis function just like any other member, some men choose to pursue surgical treatments for aesthetic reasons. “Only men with a flaccid length of less than 4 cm (1.6 inches), or a stretched or erect length of less than 7.5 cm (3 inches) should be considered candidates for penile lengthening,” research from the University of California School of Medicine recommended.

The team measured the penile dimensions of 80 men before and after drug-induced erections. They found the average penis size to be 8.8 cm (3.5 in) when flaccid and 12.9 cm (5.1 in) when erect. Interestingly, there was no correlation between erect and flaccid penis measurements – so, a group of men may be the same length when flaccid, and different lengths when erect.

If you can’t shake off concerns about your package, body dysmorphic disorder could be to blame. “Men who develop a fixation on the size of their penis are often suffering from a psychological condition called penile dysmorphophobia,” says Dr Lee. “Men who suffer from this are so obsessed with their penis size, they may not be able to work, function in society, or maintain relationships.”

How to Correctly Measure Your Penis

You can throw numbers around all you like, but if you’re measuring your member incorrectly, they don’t mean a thing. For the most accurate (and comfortable) results, use a soft measuring tape, suggests Kananai. “Place the edge of the tape where your penis starts by the pubic bone, compressing any fat around that area, and take the tape to the tip,” he says. “To measure girth, wrap the tape around the penis towards the middle.”

Now you’ve got that down, here’s how not to measure your penis: by comparing it to the length of your index finger, the size of your feet, the size of your testicles, or the model of your car. The only vaguely reliable indicator is height, and even the science behind that is shaky.

“The most consistent and strongest significant indicator of penis size was height, based on four studies in a systematic review," says Arie Parnham, consultant urologist at Pall Mall Medical. “However, it’s worth noting that the correlation was weak, and would not be a practical way to estimate penis length.”

Penis Size: Do Partners Care?

The cliche persists for a reason: it’s not how big it is, but what you do with it that counts. Guess what? You don’t need a degree in female anatomy to locate her most sensitive areas: namely the clitoris and the G-spot, “which can both be stimulated and reached with a ‘small penis’,” says Kanani.

If you’re in need of proof, science shows women aren’t bothered by penis size. “In one Dutch study, 375 sexually-active women were asked their views about penile size and its importance for sexual function,” Dr Lee explains. “77 per cent said the length of the penis was either ‘unimportant’ or ‘totally unimportant’,” Dr Lee explains.

Photo credit: Westend61 - Getty Images
Photo credit: Westend61 - Getty Images

Still think measurements matter? Look at the bigger picture. You’ve probably been too preoccupied with the measurements of your member to even consider the depth of the average vagina, but it’s between three and four inches long, albeit with the potential to expand when aroused. You might want a bigger penis, but it’s unlikely to improve your sex life.

Women judge men by their sexual performance, not their size, says porn star and sex columnist Kayden Kross. “A notable number of women tend to say that those men who believe they have large dicks tend to also believe that all they need to do is show up,” she wrote for Nylon, “while men who don’t believe they have large dicks tend to make up for it by actually trying to learn about what pleases a woman in bed.”

What Penis Size Do Women Want?

The jury is out: women don’t care about the size of your penis. But if they could design their ideal member, what would it look like? A study published in the journal Plos One set out to determine just that. Using 3D printed models, researchers asked 75 women to indicate their penile preferences by choosing from 33 different-sized models.

Interestingly, their choices varied according to the nature of the relationship. The ideal long-term partner would have a length of 16 cm (6.3 inches) and a girth of 12.2 cm (4.8 inches), while one-night-stands were slightly larger – 16.3 cm (6.4 inches) and 12.7 cm (5 inches) respectively. You’ll notice that both preferences are only just above the average penis size.

Photo credit: fizkes - Getty Images
Photo credit: fizkes - Getty Images

When it comes to measurements, studies indicate that girth is more relevant than length. In the Dutch research referenced earlier, the women who said penis length was ‘important’ or ‘very important’ for sex also heavily emphasised the importance of girth. And in a survey by University of Texas-Pan American, 45 out of 50 sexually-active women said penis width was more important than length when it came to sexual satisfaction.

What about Gay Men?

Anxiety and worries about penis size affects the type of sex gay men are having, their sexual positions and the risks they are taking, according to research by The Gay Men’s Health Project (GMFA). In a survey of 566 gay and bisexual men, 38 per cent said their penis size causes anxiety, 16 per cent said they’ve experienced derogatory comments about it, and 22 per cent admitted they’d rejected someone in the past because of their penis size.

“We recommend that you talk to your GP, sexual health professional or a counsellor about any problems you have in relation to your penis – whether that be erectile dysfunction, premature ejaculation or anxiety and self-esteem issues,” says CEO Ian Howley. “All gay men deserve to have the best sex possible. Our penises come in many shapes, sizes and skin tones – just as we do. And like us, our penises need looking after. Just don’t let your penis dictate your whole life.”

How to Increase Your Penis Size

If you’re looking to increase your penis size, you’ve probably already done a cursory Google of the various penis enlargement surgeries available. From silicone implants to fat transfer injections and suspensory ligament division, it’s a minefield out there.

“There are many clinics out there who advertise penile enlargement treatments, which fuel unrealistic expectations and promise results which are medically unfeasible,” says Parnham. “There’s a lack of good evidence to support the treatment, both in the short term and long term.”

In a robust review published in The International Journal of Impotence, researchers deemed such surgeries to be “highly risky”. “They point out that there are no standard surgical techniques for penile enhancement surgery, and many of the operations suggested are experimental,” says Dr Lee. “After surgery, a variety of complications can occur, which can shorten the penis further and worsen sexual dysfunction.”

Most men simply do not have a small enough penis to warrant the high expenses – and extreme health risks – associated with these medical procedures. In a study published in the International Journal of Impotence Research, of the 67 men who were seeking a surgical remedy for their penis size, none could be classified as having a severely short penis.

Photo credit: Busà Photography - Getty Images
Photo credit: Busà Photography - Getty Images

Ultimately, penis enhancement surgery is for men who have a micropenis. For adult men, that’s a flaccid length of under 4 cm (1.6 inches) or an erect length of less than 7.5 cm (3 inches). Even then, non-invasive techniques “such as testosterone supplementation or traction devices” should be considered first, warns Wadhwa, before you sign on the dotted line.

Want our advice? Forget surgery, and focus on what’s in your control. Trim your pubic hair, lose excess weight – if that’s a relevant factor – and place more emphasis on foreplay, says Dr Lee. Swotting up on the best sex positions for your penis size won’t hurt either. And if you're struggling with penile dysmorphic disorder (PDD), see your doctor, sexual health specialist or sex-friendly therapist.

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