Scientists do not really know the average length of a penis, but they believe it is probably around 5.1 to 5.5 inches. This is smaller than most people think.

Many people experience anxiety about whether their penis is big enough and if it will satisfy a sexual partner. This can affect a person’s self-confidence and self-image. Often, however, these fears are unfounded.

A 2020 research article notes that most males believe the average length of an erect penis is around 15.2 centimeters (cm) (Trusted Source) or 6 inches (in). In fact, the average is much smaller.

While sizes vary widely, the average length is probably 12.9–13.97 cm (5.1–5.5 in)—most likely toward the smaller end of this scale. Although results vary slightly, most studies estimate the average to be within this range.

In this article, we review facts from various scientific studies to provide a realistic answer about what to expect for average penis size.

A Note About Sex and Gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth.

When is Penis Size Too Small?

In 1996, experts carried out a study that led to guidelines for when a person may need surgery for penis enlargement. The study measured the penile dimensions of 80 males before and after drug-induced erections.

The researchers concluded that the average penis size was 8.8 cm (3.5 in) (Trusted Source) when flaccid and 12.9 cm (5.1 in) when erect.

The study also found that a person’s erect penis size did not correlate with their flaccid size. In other words, a penis may have different lengths when flaccid but similar lengths when erect. They also found no link between age and penis size.

“Only men with a flaccid length of less than 4 cm (1.6 in), or a stretched or erect length of less than 7.5 cm (3 in), should be considered candidates for penile lengthening.”

Micropenis and Buried Penis

Some individuals are born with a micropenis, meaning the penis is unusually small—usually due to hormonal or genetic factors. Although a micropenis can function normally, some may feel dissatisfied with its appearance. Hormonal treatment or surgery can increase its size if desired.

Sometimes, an average-sized penis may appear small because of extra skin around it, a condition often referred to as a buried penis. In such cases, surgery can provide a resolution.

Experts (Trusted Source) note that these guidelines are still in use.

Penises vary widely in shape and size.

What is ‘Normal’ or Average Penis Size?

Ongoing research continues to produce similar findings regarding penis size.

A 2014 review (Trusted Source) examined measurements taken by healthcare professionals for up to 15,521 males aged 17 and over. The average measurements were as follows:

• Flaccid penis length (stretched): 9.16 cm (3.6 in)
• Flaccid penis girth: 9.31 cm (3.66 in)
• Erect penis length: 13.12 cm (5.16 in)
• Erect penis girth: 11.66 cm (4.59 in)

In 2014, another study involving over 1,600 males in the United States found that the average erect penis measured 14.2 cm (5.6 in) in length and had a circumference of 12.2 cm (4.8 in).

The participants submitted their own measurements and received condoms in exchange; however, self-reported measurements can often be unreliable.

A 2019 study found that many males tend to overestimate the size of their penis when self-reporting, especially if they have had sexual experience with another person. The study surveyed 170 college-aged males, revealing that those with sexual experience were more likely to overestimate their size compared to those without such experience.

The authors speculated that sexually experienced men may have a “greater sense of masculinity, sexual competence, and prowess.”

Average Penis Size by Country

In 2007, researchers in India (Trusted Source) compiled a table listing findings on penis dimensions from various countries. Of the 16 studies cited, the earliest was conducted over a hundred years ago (published in 1899). They arrived at similar average penis lengths:

• Flaccid lengths: approximately 7–10 cm (2.8–3.9 in)
• Flaccid circumferences: approximately 9–10 cm (3.5–3.9 in)
• Erect lengths: approximately 12–16 cm (4.7–6.3 in)
• Erect circumference (from one study): around 12 cm (4.7 in)

How to Measure a Penis

To measure penis length, press a ruler into the groin and measure from the base of the penis to the tip.

To measure penis girth, wrap a measuring tape around the widest part of the penis.

Do Partners Care About Penis Size?

Some males worry about whether their penis size will live up to a partner’s expectations. However, older research suggests that penis length is not crucial for many female partners.

In one study, 77% of females who completed a questionnaire indicated that penis length was unimportant or totally unimportant, compared with 21% who declared it important or very important. Those who valued length also emphasized the importance of girth or width.

In another survey, 45 out of 50 (Trusted Source) sexually active undergraduate females stated that penis width was more important for sexual satisfaction than length.

What Size Penis Do Women Want?

A 2015 study (Trusted Source) asked 75 females to indicate their penis size preferences using 3D-printed models of 33 different dimensions. The models ranged from 10–21.6 cm (4–8.5 in) in length and 5–17.8 cm (2.5–7 in) in circumference.

The choices varied depending on the nature of the relationship being considered:

• For long-term partners: preferred length of 16 cm (6.3 in) and girth of 12.2 cm (4.8 in).
• For one-time encounters: preferred length of 16.3 cm (6.4 in) and circumference of 12.7 cm (5 in).

Overall, the desired size was slightly above the averages reported in most studies.

What About Gay Males?

Health experts have raised concerns about how anxiety over penis size affects gay males. The Gay Men’s Health Project, based in the United Kingdom, surveyed 586 males and found that 38% of respondents said their penis size causes them anxiety.

The project urges males to seek help if they have concerns, and reminds them that penises come in many shapes, sizes, and skin tones. One expert (Trusted Source) suggests that the porn industry may promote a distorted image of the “ideal” penis, contributing to this anxiety.

When to Seek Penis Enlargement?

Hormone treatments, surgery, and other techniques can increase the size of a very small penis. However, these treatments carry risks, and most individuals do not have a penis small enough to warrant such options.

Doctors typically do not recommend treatment unless the penis has a flaccid length of under 4 cm (1.6 in) or a stretched/erect length of less than 7.5 cm (3 in).

Experts are concerned about the number of males seeking surgery for penile lengthening, often due to overestimating the average size. In one study (Trusted Source) of 67 males seeking help for a short penis, none were found to be severely short.

According to a 2019 report (Trusted Source), motivations for seeking treatment often stem from issues with self-image, feelings of inadequacy, or a desire to impress others. A 2017 review (Trusted Source) noted that many individuals abandon the idea of penis enlargement once they understand the risks and potential complications.

Impact of Obesity and Age

In 2015, researchers in Saudi Arabia conducted a study involving 778 males aged 20–82 years attending a urological clinic. After medically inducing an erection, the researchers measured:

• Penis length from the skin over the pubic bone to the penile tip: 12.53 cm (4.9 in)
• Penis length from the pubic bone to the penile tip: 14.34 cm (5.6 in)
• Penis circumference: 11.50 cm (4.5 in)

The study also measured participants’ body mass index (BMI), which tends to increase with obesity. There was a weak correlation between a higher BMI and a shorter erect penile length when measured from the skin over the pubic area, but not when measured from the bone to the tip.

This suggests that the penis may appear shorter when extra fat is present at the visible base. Weight loss can often resolve this issue.

The researchers also found a small difference in size between males aged 20 and those aged 70—the difference was less than 1 cm.

Frequently Asked Questions

Is 4.5 inches erect a good size?

Penis size varies from person to person. Research (Trusted Source) suggests that the average erect penis length probably ranges from 5.1 to 5.5 inches. If you are concerned about your penis size, consider discussing your concerns with a healthcare professional.

Summary

Many males worry about the size of their penis, which can affect self-confidence and self-image. Guidelines used by many doctors indicate that the average size for a flaccid penis is around 8.8 cm (3.5 in) (Trusted Source), while the average size for an erect penis is approximately 12.9 cm (5.1 in).

Research also suggests that significantly small penises are relatively rare. If you are concerned about your penis size, it is advisable to consult a doctor or sexual health specialist for personalized advice.