What Is the Average Penis Size?

The global average is growing, but it's still smaller than you think

The average erect penis is between 5.1 and 5.5 inches in length. A 2023 study found the average erect penis length has increased by 25% over the last 29 years. Data aside, perceptions about "normal" penis size differ quite a bit.

Many wonder whether the size of their penis is what should be expected for their age, weight, height, or even race. There is truth to some of these influencing factors. Others are just myths.

This article discusses the average penis size including length and girth when soft and hard. It also explains what really does contribute to penis size.

pants with a tape measure

Riou / Getty Images

Penis Size by the Numbers

Research shows the prevailing belief that the average penis is 6 inches or longer is just a myth. Here’s a look at the average penis size based on statistics:

  • Erection length: 5.5 inches
  • Erection length, 5th percentile: 3.9 inches
  • Erection length, 95th percentile: 6.3 inches
  • Stretched penis length: 5 inches
  • Soft penis length: 3.4 inches
  • Increase in growth from soft to hard: 1.5 inches
  • Girth when soft: 3.7 inches
  • Girth when erect: 4.6 inches

(Girth describes the circumference, the measurement all the way around at the widest portion of the penis.)

Size of Your Erection

Flaccid penis size has little to do with erect penis size. Some penises can "grow more" than others during an erection.

A 2018 study in the International Journal of Impotence Research looked at two groups: one whose penises grew less than 1.5 inches from a flaccid to erect state ("showers") and those that grew more than 1.5 inches ("growers").

The study found that size while flaccid did not seem to influence growth and that:

  • "Growers" increased by an average of 2 inches.
  • "Showers" increased by an average of 1.25 inches.

The researchers also found that "growers" tended to be younger and single.

Factors That Influence Penis Size

Genetics have the strongest influence on penis size. Believe it or not, your penis size may actually be inherited from your mother.

While the science isn’t exactly clear, evidence suggests penis size is determined by the X chromosome, which males inherit from their mothers.

But genetics aren't the only influencing factor. Any of the following could also impact penis size over the course of one's lifetime:

Environmental factors during pregnancy: Things like maternal diet and exposure to endocrine disruptors like bisphenol A (BPA) in the womb can impact penis size.

Age: Penis growth is influenced by a surge of testosterone during puberty, which typically starts between the ages of 10 and 14. On average, the penis undergoes its most rapid growth between ages 12 and 16. The penis may continue to grow until a person is around 21. After that, penis size is basically "set," although older age can lead to a reduction.

Exposures during puberty: Your diet during puberty can also affect penis size. Research shows malnutrition slows genital development and delays puberty. Exposure to endocrine disruptors at this age can also slow genital growth.

Race may also influence penis size, though the research is limited. One study of Brazilian men compared penis sizes of people who identified as either Black or white. While researchers found Black penises were larger on average, the difference was only a quarter of an inch.

Sexual activity: Prolonged celibacy may also cause penis size to shrink.

Health conditions: Peyronie's disease (PD) can decrease penis size. PD typically affects older men and causes the penis to curve abnormally. Scar tissue can develop at the site of the bend, reducing penis length by as much as a half-inch.

Treatments: Some procedures, like radical prostatectomy (removal of the prostate), can shorten the penis.

Temperature: Penis size is not static and can change with temperature. When exposed to cold, a flaccid penis will shrink in size to conserve heat.

Foot Size, Height, Weight, and Your Penis Size

Despite what you may have heard, there is no correlation between a person’s foot size, height, or weight and the size of their penis.

However, a person's height and weight may create a false impression of what someone's penis size actually is.

A 2013 study from Australia found that taller men with an average-sized penis were perceived to have a "smaller" penis than shorter men with the same size penis. The same was seen when comparing overweight men to men who were slim.

This is simply the result of visual perception.

How to Measure Your Penis

Your penis will measure differently depending on whether it is soft or erect. Here are some tips to ensure an accurate measurement:

  • To measure penis length: Measure from the tip of the penis to the pubic bone by placing a ruler or flexible measuring tape on the top side of the penis during an erection. Make sure to compress any fat near your pubic bone so the ruler/measuring tape is as close to the bone as possible.
  • To measure penis girth: Wrap flexible measuring tape around the middle of the shaft. If you only have a ruler, wrap a piece of string around the shaft and measure that instead.

Does Penis Size Matter?

While the size of a penis generally does not directly affect sexual function, it can increase the risk of sexual problems and social/emotional concerns.

Studies have shown that people who think their penises are small are more likely to have:

Many people have been conditioned to believe that "size matters" and will experience stress if they feel they believe they fall short.

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

Perceptions and Behaviors

Some men believe that they will be more attractive to a partner (or perceived to be more masculine) if they have a larger penis. That is largely untrue.

According to a 2015 study in PLoS One, cisgender women shown photographs of erect penises preferred a penis size of 6.4 inches for a one-night sex partner. For a long-term partner, the preference was only slightly smaller: 6.3 inches.

In men who have sex with men (MSM), penis size commonly factors into who takes the insertive ("top") or receptive ("bottom") role during sex.

One study found that MSM with smaller erect penises (5 to 6.5 inches) are more likely to take the bottom role, while MSM with larger penises (8.5 to 13 inches) are likely to take the top role. However, it's important to note that this study was based on porn, which means it may not be relevant in the real world.

With that said, MSM are less likely to regard their penises as "small" compared to heterosexual men and far more likely to regard them as "above average."

Can You Make Your Penis Bigger?

You can make your penis bigger, but surgery is the only proven way to do so. Even then, it's not always effective or without complications.

What Doesn't Work

Diet, pills, and exercise do not in any way influence the size of the penis.

The same applies to "penis enlargement" devices like penis pumps, which do little, if anything, to increase the length of the penis.

Moreover, the improper use of these products can cause injury that affects penile function. They may increase girth if used excessively by creating scar tissues, but they can also cause permanent numbness.

The same applies to fat injections, which may nominally increase penis girth or length, but can also cause deformity or instability.


A surgery known V-Y plasty may be used to increase penis length, typically in those with a micropenis or PD. This involves cutting the ligament that anchors the penis to the pelvic bone.

Even so, V-Y plasty can destabilize the penis and cause it to turn uncomfortably while erect.

Research shows roughly one-third of people are dissatisfied with the appearance of their genitals, while one in 10 men surveyed considered genital cosmetic surgery.

What Is a Micropenis?

In adults, a micropenis is defined as a penis measuring less than 3.7 inches long when stretched but soft. This is a medical condition that affects 1.5 in 10,000 males born in the United States.

When Is a Penis "Too Big?"

Having a larger penis may not always be a good thing. In fact, a 2015 study found that, among 75 women surveyed, one of every 15 left a relationship because their partner's penis size was "too large."

There are other concerns. A large penis—particularly an uncircumcised penis—is linked to a higher risk of bacterial vaginosis (BV), an infection of the vagina. This is partly because the increased friction against the vaginal wall damages tissues and allows more bacteria in.

A larger penis poses similar risks in MSM who have anal sex, including an increased risk of HIV.


Concerns about penis size can cause stress and lead to sexual dysfunction in people who think that their penises are small. The problem is that many men think that the "average penis" is larger than it actually is.

In fact, the average length of the male penis is 5.5 inches, while the average girth is around 4.5 inches. Once puberty is completed, the size of a penis is largely "set."

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By S. Nicole Lane
S. Nicole Lane is a freelance health journalist focusing on sexual health and LGBTQ wellness. She is also the editorial associate for the Chicago Reader.