If you’re looking for reliable, clinically sourced data on penile length measurements, this guide provides the most comprehensive research-based information available. Whether you’re curious about where you fall on the spectrum, evaluating treatment options, or simply want to separate fact from fiction, the data presented here is drawn from the largest meta-analysis ever conducted on penile measurements — published in the British Journal of Urology International (BJU International), analyzing data from 15,521 men across 17 peer-reviewed studies worldwide.[1]
For a companion guide covering circumference data, see our Penile Girth Size Chart: Average Measurements & Percentile Data.
Penis Length Percentile Chart
The table below presents penile length data across percentiles for flaccid, stretched, and erect states. All data is derived from the Veale et al. (2015) systematic review, which pooled clinician-measured results from studies spanning multiple countries and ethnicities.[1]
| Percentile | Flaccid Length | Stretched Length | Erect Length | Interpretation |
|---|---|---|---|---|
| 3rd | 2.44 in (6.2 cm) | 3.11 in (7.9 cm) | 3.94 in (10.0 cm) | Well below average |
| 5th | 2.60 in (6.6 cm) | 3.46 in (8.8 cm) | 4.04 in (10.3 cm) | Below average |
| 10th | 2.83 in (7.2 cm) | 3.82 in (9.7 cm) | 4.33 in (11.0 cm) | Below average |
| 25th | 3.19 in (8.1 cm) | 4.41 in (11.2 cm) | 4.73 in (12.0 cm) | Low normal |
| 50th | 3.61 in (9.2 cm) | 5.21 in (13.2 cm) | 5.17 in (13.1 cm) | Average |
| 75th | 4.02 in (10.2 cm) | 5.71 in (14.5 cm) | 5.61 in (14.2 cm) | Above average |
| 90th | 4.41 in (11.2 cm) | 6.30 in (16.0 cm) | 6.02 in (15.3 cm) | Above average |
| 95th | 4.61 in (11.7 cm) | 6.65 in (16.9 cm) | 6.30 in (16.0 cm) | Well above average |
| 97th | 4.76 in (12.1 cm) | 6.90 in (17.5 cm) | 6.50 in (16.5 cm) | Well above average |
The percentile tells you what percentage of men have a measurement smaller than that value. For example, at the 50th percentile (average), half of all men measure smaller and half measure larger. If your erect length is 5.61 inches, you’re at approximately the 75th percentile — longer than roughly 75% of men.
Source: Veale, D., Miles, S., Bramley, S., Muir, G., & Hodsoll, J. (2015). Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15,521 men. BJU International, 115(6), 978-986.[1]
Penis Size Standard Distribution
Penile length follows a normal distribution (bell curve) across the population. This means the majority of men cluster near the average, with increasingly fewer men at the extremes. Here is what the statistics tell us:
68% of Men
Fall within one standard deviation of the mean — approximately 3.51 to 6.83 inches (8.9-17.3 cm) in erect length. This is the most common range.
95% of Men
Fall within two standard deviations — approximately 3.86 to 6.47 inches (9.8-16.4 cm) in erect length. This defines the broad “normal” range.
The difference between the 25th and 75th percentiles — where half of all men fall — is only about 0.88 inches (2.2 cm) in erect length. Small differences in actual measurement can correspond to relatively large shifts in percentile ranking, which is an important point for men evaluating where they stand.
A 2020 review found that most men believe the average erect penis is over 6 inches — nearly a full inch more than the clinically measured average of 5.17 inches.[2] This widespread overestimation is driven by self-reported studies, pornography, and cultural exaggeration. The data in this chart uses only clinician-measured values, which are significantly more reliable than self-reported figures.
Visual Distribution: Bell Curve
The following chart illustrates how erect penis length is distributed across the population. The peak of the curve represents the average (5.17 inches), with the shaded regions showing where the majority of men fall.
3.51 in
5.17 in
6.83 in
8.49 in
95% of men
Flaccid vs. Stretched vs. Erect Length
One of the most significant findings in the literature is the relationship — and the differences — between flaccid, stretched, and erect length. Understanding this distinction is clinically important and also helps explain the common “grower vs. shower” phenomenon.
Several observations are worth noting from this data:
Stretched and erect lengths are nearly identical. The average stretched flaccid length (5.21 inches) is remarkably close to the average erect length (5.17 inches). This is clinically useful because stretched length can be measured without requiring an erection, making it a practical proxy in medical settings.[1]
Flaccid length is a poor predictor of erect length. The average flaccid penis is 3.61 inches — roughly 70% of erect size. However, individual variation is substantial. Some men experience minimal change between flaccid and erect states (colloquially called “showers”), while others may nearly double in length (“growers”). Research suggests that approximately 80% of men are “growers,” particularly in colder climates.[3]
Flaccid length varies throughout the day. Temperature, stress, arousal, exercise, and time of day all influence flaccid length. Erect length is more consistent and is the standard measurement used in clinical research.
How to Measure Penis Length Correctly
Accurate measurement is essential for understanding where you fall on the size spectrum. Many men measure incorrectly, leading to inaccurate comparisons with clinical data. The method described below is the bone-pressed erect length (BPEL) technique — the same standard used in the studies that generated the data in this article.
Measurements should only be taken at full erection. Partial erections produce significantly shorter readings and will not accurately reflect your size.
Place a hard, straight-edge ruler along the top (dorsal) surface of the penis — the side facing up when you look down. A flexible tape measure can introduce inaccuracy for length.
Push the end of the ruler firmly into the pubic fat pad until it contacts the pubic bone. This is the “bone-pressed” measurement and is the clinical standard because it eliminates the variable of body fat.
Read the measurement at the very tip of the glans (head). If your penis curves, measure along the top surface following the natural line — do not straighten it.
For the most accurate comparison, measure on two or three separate occasions and average the results. Note whether this is a bone-pressed (BP) or non-bone-pressed (NBP) measurement.
The bone-pressed (BP) method is the clinical standard because it produces consistent results regardless of body composition. Non-bone-pressed (NBP) measurements will be shorter — typically by 0.5 to 1 inch depending on body fat — and should not be directly compared to the percentile chart above. If you want to compare yourself to the data on this page, use the bone-pressed method.
For information on measuring circumference, see our penile girth size chart, which includes a step-by-step guide to measuring girth correctly.
Common Measurement Mistakes
Even with a straightforward process, several common errors can produce inaccurate readings:
| Mistake | Effect on Reading | Correction |
|---|---|---|
| Measuring along the underside | Inflates length (no consistent endpoint) | Always measure from the top (dorsal) surface |
| Not pressing to the pubic bone | Underestimates length by 0.5-1 inch | Use the bone-pressed method |
| Measuring at partial erection | Significantly underestimates length | Wait for full erection |
| Using a flexible tape for length | May follow curves, adding length | Use a rigid ruler for length (tape for girth only) |
| Angling the ruler | Inflates the measurement | Keep ruler parallel to shaft, perpendicular to body |
| Measuring only once | Single readings vary by time of day or arousal | Average at least 2-3 measurements |
Length vs. Girth: What Research Says About Satisfaction
While length often receives the most cultural attention, a growing body of research suggests that girth (circumference) may be equally or more important for sexual satisfaction.
A study published in BMC Women’s Health found that women rated girth as more important than length when evaluating factors contributing to sexual pleasure.[4] The anatomical explanation is straightforward: the first 3-4 inches of the vaginal canal contain the highest density of nerve endings, and stimulation of this area is influenced more by circumferential contact (girth) than by depth (length).
A 2015 study in PLOS ONE that asked women to select their preferred penis size from 3D-printed models found the average preference was 6.3 inches in length and 4.8 inches in girth for a long-term partner — only about one inch longer and slightly thicker than the clinical average.[5]
Length
Primarily affects depth of penetration. Most relevant for certain positions. Less impactful on nerve stimulation in the anterior vaginal canal.
Girth
Provides circumferential contact with the vaginal walls. Stimulates the dense nerve endings in the first 3-4 inches. More frequently cited as important in satisfaction studies.
For men interested in the clinical data on circumference, our penile girth size chart provides the same percentile breakdown for girth that this article covers for length.
Myths Debunked
Widespread misconceptions about penis size persist despite decades of scientific research. Here are the most common myths and what the evidence actually shows:
“The average penis is 6 inches.”
The clinically measured average erect length is 5.17 inches (13.12 cm). The persistent “6 inch” myth stems from self-reported studies, which consistently overestimate by approximately 0.5-1 inch compared to clinician-measured data.[1][2]
“You can predict penis size from hand size, foot size, or height.”
Multiple studies have investigated these correlations and found them to be statistically insignificant. The Veale meta-analysis found only a weak correlation between stretched penile length and height (r = 0.2-0.6), far too low to be a practical predictor. A 2002 study in BJU International of 104 men found no predictive relationship between penile length and height, weight, or BMI.[1][6]
“Race is a reliable predictor of penis size.”
A 2014 study of more than 1,600 men in the United States found that the difference in average penis size among White, Black, Asian, Native American, and Pacific Islander men varied by less than one inch. The variation within any population group is far greater than the variation between groups.[7]
“Flaccid size accurately predicts erect size.”
Research shows no reliable correlation between flaccid and erect length. Some men with shorter flaccid penises gain proportionally more length during erection (“growers”), while others show less change (“showers”). The flaccid state is influenced by temperature, stress, and blood flow, making it an unreliable indicator of erect dimensions.[1]
“Most women prefer a very large penis.”
The Prause et al. (2015) 3D-model study found women preferred an average of 6.3 inches in length for a long-term partner — only slightly above the measured average. Additionally, women consistently rated girth as more important than length for sexual satisfaction.[4][5]
Does Penis Length Change with Age?
The relationship between age and penis size is a common concern, particularly among older men. Here is what the research shows:
Peak size is reached in late adolescence to early adulthood. Most penile growth occurs in two stages: between infancy and age five, and then during puberty (typically reaching adult size by age 17-21).[8]
Gradual changes may occur with advanced age. While the Veale meta-analysis did not find age to be a significant predictor of size, other studies have noted modest decreases in both length and firmness with age. These changes are typically attributed to reduced testosterone, decreased vascular function, and loss of elastic tissue in the tunica albuginea.[9]
Weight gain can reduce visible length. The suprapubic fat pad grows with weight gain, which reduces the visible (non-bone-pressed) length of the penis. For every 30-50 pounds of weight gain, visible penile length may decrease by approximately 0.5-1 inch. This is one reason the bone-pressed measurement is the clinical standard — it accounts for this variable.[3]
Interestingly, a 2023 systematic review and meta-analysis published in The World Journal of Men’s Health found that average erect penile length increased by approximately 24% between 1992 and 2021 across global populations — a trend researchers attributed to earlier onset of puberty, environmental factors, and changes in body composition.[10]
When to Consult a Medical Professional
For most men, size falls within the normal range and does not require medical intervention. However, there are situations where consulting a specialist is appropriate:
Micropenis. Clinically defined as an erect or stretched length of 2.5 standard deviations or more below the mean — approximately 3 inches (7.6 cm) or less when erect. This condition affects approximately 0.6% of men and may warrant evaluation by a urologist.[1]
Small penis anxiety or body dysmorphic disorder (BDD). Research shows that the vast majority of men seeking treatment for a “small penis” actually measure within the normal range. If concerns about size are causing significant distress, affecting sexual function, or interfering with relationships, professional support — whether medical or psychological — can help.[11]
Interest in enhancement options. For men who have realistic expectations and wish to explore their options, non-surgical penile enhancement procedures using hyaluronic acid dermal fillers offer a safe, effective, and reversible approach to increasing girth. These procedures primarily address circumference rather than length, though increases in flaccid length are a common secondary benefit due to the added volume and weight of the filler.
Interested in Learning More About Your Options?
Urosculpt is a physician-performed, non-surgical penile enhancement procedure using hyaluronic acid filler. Results are immediate, natural-feeling, and fully reversible.
Frequently Asked Questions
What is the average erect penis length?
According to the largest meta-analysis of 15,521 men (Veale et al., 2015), the average erect penis length is 13.12 cm (5.17 inches). This represents the 50th percentile — meaning half of all men measure above this and half measure below.[1]
What is considered a normal penis length?
“Normal” encompasses a broad range. Statistically, 95% of men fall between 3.86 inches and 6.47 inches (9.8-16.4 cm) in erect length. Any measurement within two standard deviations of the average is medically considered within normal limits.
How do I correctly measure penis length?
Use a rigid ruler placed on the top (dorsal) side of the penis. Press the end firmly against the pubic bone to account for the fat pad. Measure in a straight line from the pubic bone to the tip of the glans while fully erect. This “bone-pressed erect length” (BPEL) is the clinical standard.
Does penis size correlate with height, hand size, or shoe size?
No meaningful correlation has been established. The strongest correlation found (between stretched length and height) had an r-value of only 0.2-0.6 — far too weak to be a useful predictor.[1]
Is girth or length more important for sexual satisfaction?
Research consistently suggests that girth plays a more significant role in sexual satisfaction than length. This is because the first 3-4 inches of the vaginal canal contain the highest density of nerve endings, and these are stimulated by circumferential contact. For more on this topic, see our penile girth size chart.[4]
What is a micropenis?
A micropenis is clinically defined as an erect or stretched penis length that is 2.5 standard deviations below the mean — approximately 3 inches (7.6 cm) or less when erect. This condition affects approximately 0.6% of the male population.[1]
Can penis length be increased?
Non-surgical penile enhancement procedures using hyaluronic acid fillers primarily increase girth (circumference). However, the added weight and volume of the filler typically produces a secondary increase in flaccid length — commonly 0.5-0.75 inches. Surgical options for length augmentation exist but carry greater risk and longer recovery. Consult a qualified medical professional to discuss options specific to your goals and anatomy.
Does losing weight increase penis length?
Weight loss does not change the actual size of the penis, but it can significantly increase visible length by reducing the suprapubic fat pad. For every 30-50 pounds lost, men may see an increase of approximately 0.5-1 inch in visible (non-bone-pressed) length.
References
- Veale, D., Miles, S., Bramley, S., Muir, G., & Hodsoll, J. (2015). Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15,521 men. BJU International, 115(6), 978-986. DOI: 10.1111/bju.13010
- Lever, J., Frederick, D. A., & Peplau, L. A. (2006). Does size matter? Men’s and women’s views on penis size across the lifespan. Psychology of Men & Masculinity, 7(3), 129-143.
- Mondaini, N., Ponchietti, R., Gontero, P., et al. (2002). Penile length is normal in most men seeking penile lengthening procedures. International Journal of Impotence Research, 14, 283-286.
- Eisenman, R. (2001). Penis size: Survey of female perceptions of sexual satisfaction. BMC Women’s Health, 1(1), 1.
- Prause, N., Park, J., Leung, S., & Miller, G. (2015). Women’s preferences for penis size: A new research method using selection among 3D models. PLOS ONE, 10(9), e0133079.
- Mondaini, N., Ponchietti, R., Bonafe, M., et al. (2001). Penile length and circumference: A study on 3,300 young Italian males. European Urology, 39(2), 183-186.
- Herbenick, D., Reece, M., Schick, V., & Sanders, S. A. (2014). Erect penile length and circumference dimensions of 1,661 sexually active men in the United States. The Journal of Sexual Medicine, 11(1), 93-101.
- Schonfeld, W. A. (1943). Primary and secondary sexual characteristics: Study of their development in males from birth through maturity, with biometric study of penis and testes. American Journal of Diseases of Children, 65(4), 535-549.
- Wylie, K. R., & Eardley, I. (2007). Penile size and the ‘small penis syndrome.’ BJU International, 99(6), 1449-1455.
- Briken, P., Dekker, A., Cerwenka, S., et al. (2023). Worldwide temporal trends in penile length: A systematic review and meta-analysis. The World Journal of Men’s Health, 41(4), 848-860. DOI: 10.5534/wjmh.230078
- Veale, D., Miles, S., Read, J., et al. (2015). Phenomenology of men with body dysmorphic disorder concerning penis size compared to men anxious about their penis size and to controls. Body Image, 13, 53-61.
This article is provided for educational and informational purposes only. It is not intended as medical advice. If you have specific concerns about your anatomy, sexual health, or are considering any medical procedure, consult with a qualified healthcare provider.