Average Penis Size: According to Science

Measuring tape next to a cucumber and banana
Written by

Content by

Last Updated

Last Updated

Finding it hard to get hard?

Delievered the next day in plain and discreet packaging

Admit it. You’ve wondered whether or not you ‘size up’ against the competition.

For the bold, a Google search will surface dozens of articles, each claiming to possess the ultimate answers, to what is likely a centuries-old question.

But how does one navigate a plethora of false information to uncover the truth?

Presented below are the facts when it comes to the average size of the male reproductive organ, with insights and tips on how to measure yourself inch-by-inch, against your fellow man.


The ‘Magic Number’

Six inches. It’s the number most males have been led to believe, is the average penis size. But is this commonly accepted number true in regards to the average penis length?

Not quite. According to a study published by the National Library of Medicine (NIH), the average length is in fact between 12.95 - 13.97cm (5.1 - 5.5in). As indicated in the report, oft-cited studies – mixed with a bit of good old-fashioned exaggeration – have led more than a fair share of men to believe that the average penis size is longer than it is. The study notes that many self-reported measurements regarding penile size come in at 6.63 inches for heterosexual men, and even longer for homosexuals. 

The exaggeration of penis size is attributed to the measurements being determined by clearly-invested parties – the men themselves, who may suffer from body dysmorphic disorder and not feel as though they stack up against societal-ideals of masculinity. In other words, men are likely to overestimate the size of their penis to make themselves feel good. So, a 6 inch penis is actually bigger than average. 

Now that we’ve established the truth about the average penis size – and admitted a man’s tendency to over-measure on occasion – let’s examine how the average penis length is perceived around the world, and if any determinations can be made regarding size averages by country. 


The average penis size by country

The truth is - it varies. Referencing another oft-used expression… variety is the spice of life. But is there some significance to the average penis size based on continent? 

According to WorldData.info, no other question has been asked as frequently as inquiries into the average length of the male genitalia.

Presented below are some interesting insights into the average penis size, as determined by country of origin. 

Infographic which shows a worldwide comparison of penis sizes by country

Some interesting observations: 

  • The longest average penis size is boasted by men in Ecuador, with a reported 17.62cm (6.9in) compared to the average male height of 1.67m (5’5³/₄”). The average penis size amounts to an astonishing 10.54% of total height.
  • The runner-up in terms of average penis size belongs to the men of Cameroon, with 16.67cm (6.56in) contrasted against an average height of 1.71m (5’7³/₈”). This accounts for 9.75% of total height.
  • The US claims 13.58cm (5.35in) against an average height of 1.77m (5’9⁵/₈”), or 7.68% of total height.
  • The UK ranks at number 66 of 86 listed countries, with an average penis size of 13.13cm (5.17in) measured against an average height of 1.78m (5’10¹/₈”), with the percentage accounting for 7.38% of total height.


Having established the areas of the world and their claims to the ideal length, the time has come to see how you, measure up.


How to measure your penis

As is the case with many delicate operations, there exists a proper procedure when it comes to measuring your penis. The presence of a good, firm erection is key to obtaining the proper diagnostic data.

As illustrated below, the ideal way to measure the length of the penis is to position your measuring instrument of choice against the root of the shaft and extend alongside the upper side all the way until you reach the tip.

As pertains to the correct measurement of the circumference, wrap the measuring device gently around the thickest part of the shaft, taking note of where the two sides of the measuring tape meet.

Having gathered the relevant data, it is also worth mentioning that you will likely also want to measure your flaccid penis. Let’s take a look at the relative norms for the average flaccid penis length.

Average penis size unerect 

Research published by the National Library of Medicine (NIH) claims the average size of a flaccid penis is 9.16cm (3.6in) while a stretched flaccid penis nets a girth measurement of 9.31cm (3.66in).


Average erect penis size

The above research also examined the measurements of a fully erect penis. The average erect penis length is 13.12cm (5.16in), while the average erect penis girth is 11.66cm (4.59in). 


How does the UK measure up?

The average penis size in the United Kingdom is 13.13cm (5.17in). Englishmen may be delighted to learn that the UK is decidedly, well – average – when it comes to penis size. While by no means as well-endowed as our chart-leading brethren from Ecuador or Cameroon, residents of the UK have bragging rights over some of the folks over in Southeast Asia.


Can you explain penis size?

Unfortunately, no. While there has been some significant scientific research attributed to the reasonings behind penis size variations, the truth of the matter is that – much the way our individual heights vary – the length and girth of our sexual reproductive organs is a mystery, encoded largely in genetics and biology. 

As explained in a verywellhealth.com article, we can thank our parents for the sex chromosomes that factor in to the size of our penis. The combination of our father’s Y chromosome, containing the ‘male-determining’ or SRY gene, partners up with our mother’s X chromosome, in order to spin the genetic wheel of fortune that results in our penis size.

It is believed that the wildly unique makeup of the X chromosome is the ultimate decider for who gets a large penis, and explains why a set of genetic male siblings may end up with very different members. 


What affects size?

Perhaps the second most popular question, following the query into the average size of the male reproductive organ, is whether any external factors can influence or improve the size of the male penis.

While no amount of supplements or well-wishing can improve the size of your penis, it is true that erectile dysfunction (ED), can negatively influence the mightiness of a presented penis.

ED reduces the amount of blood that is able to flow to the penis during erection, and therefore limits the firmness of the penis. Less blood available during an erection results in a smaller erection (or one that doesn’t fulfil is potential).


Let’s take a look at some of the culprits that contribute to erectile dysfunction:

  • Diabetes. Erectile dysfunction is common amongst males with diabetes, especially Type 2 diabetes. This is attributed in part to damaged nerves and blood vessels caused by poor long-term blood sugar control. Some research suggests ED could be a precursor signal of diabetes. 
  • Obesity. Overweight and obese individuals increase the risk of erectile dysfunction by 30-90% when contrasted against those within a healthy weight range, according to a study published by the International Journal of Impotence Research.
  • Heart disease. A study published by The Mayo Clinic suggests the dysfunction of the inner lining of the blood vessels (endothelium) and smooth muscle causes inadequate blood supply to both the heart and penis.
  • Low testosterone. Testosterone levels are contributors to a male’s ability to achieve an erection. The mix of low testosterone, decreased blood flow to the penis and a corresponding psychological anxiety regarding lack of performance inevitably lead to the onset of ED.
  • Conditions affecting blood flow. The Cleveland Clinic attributes hypertension and high cholesterol as potential contributors to the progression of erectile dysfunction in males.
  • Nerve damage. Spinal cord injuries, as well as neurological conditions such as multiple sclerosis, Alzheimer’s and Parkinson’s disease can affect the ability for the spinal cord to activate the autonomic preganglionic neurons that innervate the penile erectile tissue. (A fancier way of saying that nerve damage or neurological conditions can block the nervous system from signalling the penis to become erect.)

If you believe that you’re experiencing the symptoms of ED, consult a medical professional. Rest assured, however, there are options available to help you achieve an erection.


What are my options if I’m experiencing ED?

Thanks to the miracles of modern science, solutions for erectile dysfunction are readily available. The most common ED treatments that are used to help men to re-establish their peak include:


Of course, medication isn’t the only available course of action when combating the presence of ED. In order to help you win the battle for your ultimate erection, here are some other applications to consider:

  • Penis pumps. First of all, they work. Otherwise known as a penis vacuum pump, these devices draw blood into the penis, allowing an erection firm enough to accomplish the task at hand. They remain a popular choice amongst men for whom ED medication is not a viable option.
  • Cock rings. Another popular choice for men seeking a firm erection, penis rings or constriction bands work by keeping blood flow in the penis for an extended period of time. By slipping the ring around the base of the penis, cock rings restrict the flow of blood away from the penis.
  • Therapy. Depression, stress and anxiety can contribute to the perfect storm that is erectile dysfunction. Consulting a professional can often aid in diagnosing the internal factors presenting very real external problems. The introduction of a therapist or cognitive behavioural therapy (CBT) treatments can help alter the way you think, which could have positive physical outcomes.
  • Lifestyle changes. Don’t underestimate the importance of sleep, maintaining a healthy weight, and an active physical health regimen as factors influencing your sexual health. 

As always, be sure to consult a medical professional should you have any questions regarding your perception of your sexual well-being…and don’t underestimate the power of communication. Communication with your partner, a therapist, friends.


What is the best penis size according to women?

Here is yet another popular misconception amongst men – that most women have a penis size preference.

Some males worry about whether their penis size will live up to the desires of a partner.

However, other research suggests that a larger penis is not important for many female partners.

In one study, 77% of females who completed a questionnaire said penis length was unimportant or totally unimportant, compared with 21% who declared it was important or very important. Those who said that length mattered to them also stated that girth, or width, was more important.

In another survey, 45 out of 50 sexually active undergraduate females said that penis width was more important to sexual satisfaction than penis length.


Size doesn’t matter, your mentality does

The size of a penis generally does not directly affect sexual function, it can increase the risk of sexual problems. Studies have shown that people who think their penises are small are more likely to have low self-esteem, sexual performance anxiety, relationship problems, and ED

They are also less likely to let others, including doctors, look at their penis. 

Trusting in the confidence of both medical professionals and your partner can go a long way towards re-establishing a healthy perception with your penis. Whether you’re concerned about length, girth or performance, rest assured you’re not alone…and, as this article proves, you’re one of over 4 billion males who will at one time or another, question their penis (or the size of it at least).

Whilst all of our content is written and reviewed by healthcare professionals, it is not intended to be substituted for or used as medical advice. If you have any questions or concerns about your health, please speak to your doctor.