Normal Penis Size: What Research Shows and When to Seek Advice

💡What research says about normal penis size

The most widely cited study is a systematic review published in BJU International in 2015 by Veale and colleagues. According to King’s College London, it pooled 17 studies in which health professionals measured men using a standard method, rather than relying on self-reported sizes. According to the review, the averages were:

The authors built charts (nomograms) showing the spread of normal sizes. According to King’s College London, the lead author said these charts should help doctors reassure the large majority of men.

2How penis size is measured

Doctors usually measure the stretched penile length. According to the StatPearls review on micropenis, the penis is gently stretched and measured along its upper side from the pubic bone to the tip, with the fat pad above the penis pressed down so that it does not hide part of the shaft. Several readings may be averaged. Home measurements are often inaccurate.

🔍Why size can look different

• Temperature and relaxation: according to West Yorkshire Healthier Together, relaxed length changes with things like temperature, while erect sizes vary less between people than relaxed sizes.
• Relaxed size does not predict erect size: Mayo Clinic notes that flaccid length is not a reliable guide to erect length.
• Body weight: according to Mayo Clinic, excess belly fat can make the penis look shorter than it is. The StatPearls review notes that many boys referred for a “small penis” have a large fat pad above the pubic bone hiding a normally sized penis (a buried or concealed penis).
• Height: the Veale review found only a small-to-moderate link between height and length.

A healthy weight supports general men’s health.

4Small penis anxiety and body image

Some men with a normal-sized penis feel strongly that it is too small. Researchers describe two levels of concern. Small penis anxiety is excessive worry about size. Penile dysmorphic disorder, a form of body dysmorphic disorder (BDD), is a deeper preoccupation that causes marked distress or affects daily life. According to King’s College London, BDD gives a person a distorted view of how they look.

A cohort study by Veale and colleagues in Sexual Medicine compared 90 men: 26 with BDD about penis size, 31 with small penis anxiety and 33 without such concerns. According to the study, men with BDD reported more sexual difficulties, including erection problems, and both worried groups were more likely to try methods such as stretching or pumps, with little success. The authors say psychological treatments for these men still need development and testing. If worry is affecting your mood, relationships or erections, it is worth discussing; see also our guide to erectile dysfunction.

🔬Micropenis: a medical diagnosis in babies and children

Micropenis is uncommon and is defined by measurement, not by appearance. According to StatPearls, it means a stretched length more than 2.5 standard deviations below the average for age, in a penis that is otherwise normally formed. Because the reference limit depends on age, a doctor compares the measurement with age-specific charts. It is usually found at birth or in early childhood and is often linked to reduced hormone levels before or after birth, so specialists may test hormones, including testosterone; see our guide to low testosterone. Treatment, when needed, is decided by the specialist team.

🔍Why enlargement products are not recommended

Mayo Clinic states that there is little scientific support for non-surgical enlargement methods and that some can cause permanent damage.

Any treatment for a genuine medical problem is decided by the doctor after assessment.

7How a doctor assesses size concerns

A urologist will usually ask about your concern, how long it has been present and how it affects you, check for erection problems, and examine the penis and testicles. The doctor may measure stretched length, look for a buried penis caused by fat, and check for curvature or lumps. Hormone tests are considered only if there are signs of a hormonal problem. For most men, the result is reassurance that their size is normal. Where worry is severe, the doctor may suggest psychological support.

⏰When to see a doctor

• A new curve, a hard lump, or painful erections: according to the NHS, these should be checked by a GP and can be signs of penile curvature (Peyronie’s disease).
• Erection problems that make sex difficult.
• A baby or child whose penis looks very small or hidden, or where the testicles cannot be felt.
• Worry about size that causes distress, avoidance of relationships, or attempts to use enlargement products.
• Any pain, swelling or injury after using a pump, device or injection, which needs prompt medical care.

❓Frequently asked questions

10Sources

1. "Am I normal?" A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15,521 men (Veale et al., BJU International, 2015)
2. Am I normal? An analysis of penis lengths (King's College London)
3. Sexual Functioning and Behavior of Men with Body Dysmorphic Disorder Concerning Penis Size Compared with Men Anxious about Penis Size and with Controls: A Cohort Study (Veale et al., Sexual Medicine)
4. Micropenis (StatPearls, NCBI Bookshelf)
5. Penis-enlargement products: Do they work? (Mayo Clinic)
6. Peyronie's disease (NHS)
7. My penis and testicles (West Yorkshire Healthier Together, NHS)