Average Penis Size By Age: Does Size Change As You Get Older?

Short answer: Once puberty is over, penis size stays essentially the same for the rest of a man’s life. In The Definitive Penis Size Survey, the differences in average size between adult age groups up to 49 were small enough to be random sampling error, and men over 50 showed only a slight decline in length. What does change with age is how big the penis looks and how firm erections get, and most of that is caused by things you can do something about.

Average Penis Size For Adult Men

Before looking at age, it helps to know what average actually is. The most reliable figures come from a 2015 review in BJU International by Veale and colleagues, which pooled measurements taken by health professionals from more than 15,000 men:

Measurement	Clinical Average
Erect length	5.2″ (13.1 cm)
Erect girth	4.6″ (11.7 cm)
Flaccid length	3.6″ (9.2 cm)
Flaccid girth	3.7″ (9.3 cm)
Stretched flaccid length	5.2″ (13.2 cm)

Our own survey, where men measured themselves, came in higher, at an average erect length of 6.4 inches. Self-reported numbers almost always run high, so the clinical figures above are the better benchmark. You can see exactly where you fall on both with our Penis Size Visualizer.

Penis Size By Age: What The Survey Found

The Definitive Penis Size Survey collected measurements from 2,545 adult men across a wide age range. The results by age were clear:

• Adults under 50: The variation in average size between age groups was not statistically significant. A 25-year-old and a 45-year-old in the survey had, for practical purposes, the same average size.
• Men over 50: There was essentially no difference in overall size compared with younger men, apart from a slight, gradual decline in reported length. The sample of older men was modest, so it is not certain whether that decline is real or a statistical quirk.

That matches what doctors see. Penis size is set by the end of puberty, and the penis does not keep growing in adulthood or shrink dramatically in middle age.

Penis Size By Age At A Glance

Age	What To Expect
Late teens to early 20s	Growth finishes as puberty ends. Timing varies a lot from person to person.
20s and 30s	Adult size is stable. Erections are typically at their firmest.
40s	Size is unchanged. Weight gain and early changes in blood flow can make the penis look or feel smaller.
50s and 60s	A small loss of erect length is possible, usually linked to blood flow, tissue elasticity or weight.
70s and beyond	Further modest shortening is common, especially with erectile problems or after prostate treatment.

When Does The Penis Stop Growing?

The penis grows during puberty, driven by testosterone. For most men, growth is finished by the late teens or early 20s, though the exact timing varies widely. There is no growth after that point, and nothing you do as an adult will restart it.

If you are a teenager reading this and worried about your size, the most important thing to know is that you are probably still developing, and comparing yourself to adult averages, or to other guys your age, tells you very little. If you have concerns, talk to your doctor. It is a routine question for them.

Why The Penis Can Seem To Shrink With Age

Many men in their 40s and older feel like they have gotten smaller. Usually the penis itself has not changed much. Something around it has.

Weight Gain

This is the most common reason by far. The base of the penis is surrounded by the pubic fat pad. As belly and pubic fat build up, they bury part of the shaft, so less of it is visible. Losing weight often “gives back” length that was hidden, not lost.

Reduced Blood Flow

Erections depend on healthy blood vessels. With age, high blood pressure, high cholesterol, diabetes and smoking all reduce blood flow, which can mean erections that are less full and slightly shorter.

Less Elastic Tissue

Over decades, the tissue inside the penis can lose some of its stretch. This is gradual and usually amounts to a small change in erect length.

Peyronie’s Disease

Scar tissue inside the penis can cause a new bend, pain and a loss of length. It becomes more common with age. If you notice a new curve or a lump, read our guide to Peyronie’s disease and see a urologist.

Prostate Cancer Treatment

Surgery or radiation for prostate cancer is linked to measurable penile shortening in many men. If you are facing treatment, ask your urologist about penile rehabilitation, which can help preserve length and function.

How To Keep What You Have As You Age

• Stay at a healthy weight. It is the single biggest factor in how much of your penis is visible.
• Look after your heart. What is good for your blood vessels, such as regular exercise, not smoking and managing blood pressure and blood sugar, is good for your erections.
• Keep having erections. Regular erections help keep penile tissue healthy and elastic.
• Train your pelvic floor. Kegel exercises have clinical evidence for improving erectile function. See our guide to penis exercises that actually work.
• See a doctor early for erectile problems, a new curve or pain. Erectile problems can be an early warning sign of heart disease.

Can You Increase Size At Any Age?

Pills, pumps and hand exercises have not shown lasting gains in research. The one non-surgical method with clinical evidence for added length is penile traction, a device worn for several hours a day over several months. A review in BJU International found extenders produced an average gain of about 1.8 cm. Traction works the same way at 25 or 55, and it is also used by urologists to help preserve length in men with Peyronie’s disease. SizeGenetics is the only extender we recommend.

Frequently Asked Questions