What’s the average penis size? Probably smaller than you think

Reviewed by Yael Cooperman, MD, Ro, 

Written by Michael Martin 

Reviewed by Yael Cooperman, MD, Ro, 

Written by Michael Martin 

last updated: Feb 08, 2024

4 min read

A lot of guys have some anxiety about the size of their penis–how does it look? Is it big enough to satisfy their partner? If you watch a lot of porn, you might be inclined to believe that the average penis reaches great lengths of 9 or 10 inches, but this simply isn’t true. While scientists don’t know precisely how big the average penis is, the research has shown that it’s probably not as big as you think. 

The average erect penis probably falls between 5.1 and 5.5 inches. Some people are bigger, some are smaller. But if it’s working for you and your partner(s), it’s just fine. Continue reading to learn more about the average penis size.'

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Average penis length 

A 2015 research review found that the average erect penis size is approximately 5.17 inches long (13.12 cm). The average length of a flaccid penis is approximately 3.6 inches (9.16 cm) long. Some people’s penises do more “growing” when they’re hard than others, meaning that the gap between how long your penis is when it’s soft or hard can vary. 

Why, then, do so many people think the average penis size is more than 6 inches long? In addition to inaccurate penis representation in porn, we can thank a researcher named Alfred Kinsey for that. He and his colleagues published a report in the 1960s that claimed that the average penis size was over 6 inches. Unfortunately, that number has cemented itself deep in our psyche. After more extensive research on the topic, we now know that it was an overshoot of about 20% beyond the actual number.

Average penis girth

Penis girth—aka the circumference, better known as “how thick it is”—gets a lot of attention in the world of sex and sexual health. The average circumference, or girth, of an erect penis is 4.84 inches (9.31 cm), and the average girth of a flaccid penis is 3.67 inches (9.31 cm). 

How many people have penises that are 7 inches or more?

It’s rare. Super rare. According to the available research, just one in a hundred guys have a penis that measures between 7–8 inches erect. 

Numerous studies have found that Kinsey’s original estimate of 6 inches is nearly a full inch longer than the true average. While we’ll take his findings with a grain of salt, Kinsey’s other research showed that extremely large penises (over 7–8 inches) are exceedingly rare. In fact, the original Kinsey penis-size survey found that only:

  • 1% of penises fall between 7–8 inches long

  • 6 in 1000 penises (0.6%) are 9-inches long

  • Just over 0.2% of penises are longer than 9 inches—that’s 2 in 1000

Up to 90% of penises are within an inch of the average size. Statistically speaking, that means most people have a “normal-sized” penis. 

What is a micropenis?

Approximately 0.6% of people worldwide are born with a true micropenis. Healthcare providers determine if a penis is a micropenis based on stretched penis length (SPL)––for adults, an SPL of 3.67 inches or less falls into the category of micropenis. Patients with micropenises often report dissatisfaction with the appearance of their penis, but their sexual function is typically fine. 

Does penis size matter?

If you’re worried about whether or not your penis is large enough to satisfy your partner, rest assured that your partners are probably not nearly as interested in your penis size as you are. In a survey of 170 heterosexual women, only 1% of women found the length of a penis “very important.” Fifty-five percent of women found the length of a penis “unimportant,” and 22% of women found it “very unimportant”.

No matter your size, if you have a penis, remember this: there are more ways to please your partner than penetration. Honest communication about you and your partners’ likes and dislikes is the key to good sex. 

How to measure your penis

Knowing your penis size, and knowing how to measure your penis correctly, is important when it comes to choosing the right condom size. In fact, choosing the right condom might be the only instance where size actually matters. If your condom is too tight or too loose it can cause performance issues, such as condom-associated erectile problems and an inability to ejaculate, and/or unwanted pregnancy or exposure to STDs. 

To identify what size condom you need, you should measure the length and the girth of your penis with a tape measure. Once you know these two measurements, you can check different brands in-store or online and choose a condom that most closely matches your erect penis size.

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How to make your penis bigger

While most penises are a perfectly adequate size, many people are still unsatisfied with the size of their penis and want to find ways to make it bigger. If your penis falls in the normal range but you’re still bothered by the size of your penis, you may have what some researchers call penis anxiety or penis dysmorphic disorder (PDD—a type of body dysmorphic disorder). 

In some cases, though, especially if you’re in the rare group of people with a micropenis, penis enlargement procedures or devices may be able to help. 

The truth is, if your penis allows you to have a pleasurable sex life with yourself and your partner(s), your penis is the perfect size. However, if you have concerns about your sexual function, make an appointment with your healthcare provider.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

February 08, 2024

Written by

Michael Martin

Fact checked by

Yael Cooperman, MD

About the medical reviewer

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.

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