How do you measure your penis correctly, according to a urologist

If you have ever wondered “how do you measure your penus” or worried that you do not stack up, the real answer starts with using the same method urologists use in clinic and research.

“Most men have never been shown how to measure their penis in a standard way. Once we do it correctly, the numbers are usually very normal and a lot of anxiety fades quickly.”

Alexander Grant, MD, PhD

If you are typing “how do you measure your penus” into a search bar, you are not alone. Studies show that many men badly misjudge their own size, and self-reported numbers are usually larger than careful measurements done by clinicians.^[1],[2]

When urologists measure in a standardized way, the average erect penis is about 5.1 to 5.5 inches long, with an average erect girth – the thickness around the shaft – of about 4.8 inches.^[1],[2] Yet in surveys where men measure themselves at home, reported averages often jump above 6.7 inches. That gap tells you how unreliable random home methods can be.

On top of that, social pressure to be “big” feeds penile dysmorphia, a body image problem where a man is convinced his normal penis is too small. Measuring correctly is not about bragging rights. It is about using the same playbook doctors use, so you can buy condoms that fit, spot real health changes, and stop comparing yourself to myths.

The relationship

Penis size, how you measure it, and how you feel about it are tightly connected. Medical studies that use trained staff and strict protocols consistently find average erect lengths just above 5 inches, but online polls where men report their own numbers often look an inch or more larger.^[1],[2] The difference is not biology. It is tape-measure technique and a strong urge to round up.

That gap between myth and reality can cause real distress. Men who overestimate what is “normal” are more likely to think they are small even when their measurements fall squarely in the typical range. In some cases this becomes penile dysmorphia, a form of body dysmorphic disorder where obsessive focus on penis size leads to anxiety, avoidance of sex, or risky pursuit of unproven enlargement methods.

From a health standpoint, the measurement that matters most is condom fit and changes over time, not how you rank against other guys. Size only becomes clinically important when your penis is far outside the usual range for your age, when there is clear loss of length, new curvature, or when size concerns are tied to symptoms like erectile dysfunction.

How it works

If you really want to know “how do you measure your penus” the way urologists do, you need a clear plan and the right tools. The gold standard is bone-pressed erect length and mid-shaft erect girth, measured with a firm ruler and a flexible tape or string.^[1],[3]

Why you should measure when erect

Most research reports erect length, meaning the size when your penis is fully hard during sexual arousal, because flaccid length varies a lot with temperature, stress, and room conditions.^[1] A cold shower, tight underwear, or anxiety can easily shrink flaccid length by an inch or more even though the actual erectile tissue has not changed.

For that reason, urologists either measure with a full erection or use stretched flaccid length, a method where the soft penis is gently pulled to its natural limit, which closely predicts erect size. Either way, you want to remove the day-to-day variability from the equation.

How to measure erect length step by step

Clinics use bone-pressed length, which means pressing the ruler down to the pubic bone to cancel out fat at the base and standardize the starting point.^[1],[3] Here is how to copy that at home:

Get a rigid ruler with millimeter or 1/16-inch markings.
Achieve a full erection without bending the shaft downward.
Stand upright. Place the ruler on the top side of the penis, centered along the shaft.
Press the base of the ruler straight back into the pubic area until you feel the firm resistance of the pubic bone.
Read the measurement at the tip of the glans, the rounded head of the penis.

That number is your bone-pressed erect length. It is directly comparable to measurements reported in medical research, where the average is about 5.1 to 5.5 inches.^[1],[2]

How to measure erect girth (thickness)

Girth is the circumference of the shaft, measured all the way around. Most studies use mid-shaft erect girth, taken halfway between the base and the head of the penis.^[1],[2]

Use a soft measuring tape, like the kind used for sewing. If you do not have one, use a piece of string and then lay it against a ruler.
With a full erection, wrap the tape once around the middle of the shaft without squeezing the tissue.
Record the number where the tape meets itself. That is your mid-shaft erect girth.

Across large samples, average erect girth is roughly 4.8 inches, with plenty of men falling above and below that number and still being completely normal.^[1],[2]

Stretched length when you cannot measure an erection

Stretched flaccid length is the distance from the pubic bone to the tip when the soft penis is gently pulled straight until you first feel resistance, but not pain. In clinic, this is often used instead of an erect measurement and has been shown to closely track erect length in most men.

Stand upright and let the penis hang naturally.
Place a rigid ruler on the top side, press it to the pubic bone.
With the other hand, grasp just behind the glans and gently stretch straight out.
Read the distance from the pubic bone to the tip while maintaining the stretch.

This method is useful if getting and holding an erection is difficult, for example if you have erectile dysfunction, a condition where it is hard to achieve or maintain a firm erection.

When hormones and health tests matter

Testosterone, the main male sex hormone, helps drive libido, erections, and the maintenance of penile tissue and pelvic muscles. Severe or long-standing testosterone deficiency can contribute to weaker erections, loss of muscle, more body fat, and a “buried” looking penis as the fat pad in front of the pubic bone grows.

Meta-analyses suggest that symptomatic men with total testosterone below about 350 ng/dL (around 12 nmol/L) or free testosterone below about 100 pg/mL are the most likely to benefit from testosterone therapy when other causes have been addressed. If your penis seems shorter because it never gets fully firm, or if size worries come with low drive, fatigue, or depressed mood, blood tests for hormones and cardiovascular risk factors can be part of the workup.

Conditions linked to it

Worry about penis size and questions like “how do you measure your penus” can be early clues to several physical and psychological conditions. Measuring correctly helps your doctor spot them and track change over time.

Penile dysmorphia. This is a form of body dysmorphic disorder where a man is preoccupied with the idea that his normal-sized penis is too small, even when measurements fall squarely in the typical range. It often shows up as obsessive measuring, constant comparison, and avoidance of sex or locker rooms.

Peyronie’s disease. Peyronie’s disease is a condition where scar tissue forms in the tunica albuginea, the fibrous casing of the penis, leading to curvature, loss of length, and sometimes painful erections.^[4] Men often first notice that their penis looks shorter or bends sharply when erect compared with earlier years.

Buried penis and obesity. Significant weight gain, especially in the lower abdomen, can create a large fat pad that partially buries the base of the penis. Bone-pressed measurements help separate true loss of length from the visual effect of more fat at the base.^[4]

Rare true size disorders. True micropenis, an unusually small penis based on strict medical charts for age, is usually diagnosed in childhood. In adults, very small measured size combined with underdeveloped testes or delayed puberty signs can point to lifelong hormone problems that deserve endocrine evaluation.

Limitations note. Most of the links between penis measurements, mental health, and physical disease come from observational studies in men who showed up to clinics or surveys. That means we can see associations, but a smaller or larger size by itself is not a proven cause of other health problems.

Symptoms and signals

Here are signs that it is worth talking to a urologist or men’s health clinician about your measurements:

Your bone-pressed erect length or mid-shaft girth seems far below published averages and the worry is starting to affect your confidence, relationships, or sexual activity.
You notice clear loss of length compared with past measurements, especially if it comes with new curvature, pain, or bending during erection.
Your penis looks “shorter” because it is partly hidden in a growing fat pad at the base, or the skin around the base looks inflamed, scarred, or tight.
You cannot achieve a firm erection, or your penis does not become as full as it used to, so it appears smaller when hard.
You find yourself measuring obsessively, checking mirrors often, or avoiding sex or communal showers because of shame, even though your numbers are within the normal range.
Condoms consistently feel too loose or painfully tight, no matter which standard brand or style you use.

What to do about it

If you are still wondering “how do you measure your penus and what should I do with the number,” use this simple three-step plan.

Measure once, the right way. Use bone-pressed erect length and mid-shaft erect girth, with a rigid ruler and flexible tape. Write the numbers down and resist the urge to keep re-measuring every day. Recheck only if something clearly changes.
Check the rest of your health. If measurement anxiety comes with erectile problems, fatigue, low sex drive, or big weight changes, ask your doctor about a full checkup. This can include testosterone, cholesterol, blood pressure, blood sugar, and a focused genital exam. Men with total testosterone persistently below about 350 ng/dL or free testosterone below about 100 pg/mL, plus clear symptoms, are the ones most likely to benefit from hormone treatment after other causes are ruled out.^,[5]
Monitor function, not just size. Track how reliably you get and keep an erection, whether sex feels good for you and your partner, and how you feel about your body. If those areas are solid, your measurements are doing their job, even if they do not match porn or locker-room talk.

Myth vs Fact

Myth: There is one “normal” penis size and anything smaller is a problem.
Fact: Large studies show a wide normal range. The average erect length is about 5.1 to 5.5 inches, with most men clustered within about an inch of that in either direction.^[1],[2]
Myth: Flaccid size predicts erect size.
Fact: There is only a weak link. Some men are “growers,” with small flaccid length and big increases when erect. Others are “showers,” looking larger when soft but gaining little with erection.^[1]
Myth: Bigger is always better for partners.
Fact: Studies where people rate images suggest only a modest preference for lengths around 6.3 inches, and real-world satisfaction depends far more on arousal, communication, and technique than on size alone.
Myth: Pills, lotions, or random pumps can safely add inches.
Fact: There is no solid evidence that over-the-counter pills or creams increase penis size, and unsupervised use of pumps or devices can cause bruising or scarring. Some traction devices may give modest gains under medical supervision, but expectations need to be realistic.^[4]
Myth: If you measure below average, sex cannot be satisfying.
Fact: Partners’ bodies are flexible, and there is no single “required” size for pleasure. Comfort, arousal, and emotional connection matter much more than small differences on a ruler.

Bottom line

Knowing how to measure your penis – or, as search engines often see it, “how do you measure your penus” – is about using a consistent, clinically tested method, not chasing a bigger number. Bone-pressed erect length and mid-shaft girth put you on the same page as urologists and research studies. For most men, those measurements land squarely in the broad normal range. When they do not, or when size worries start to squeeze your confidence or sex life, that is a signal to talk with a professional who can look beyond the ruler to your hormones, mental health, and overall function.

References

Veale D, Miles S, Bramley S, et al. 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. 2015;115:978-86. PMID: 25487360
Herbenick D, Reece M, Schick V, et al. Erect penile length and circumference dimensions of 1,661 sexually active men in the United States. The journal of sexual medicine. 2014;11:93-101. PMID: 23841855
Wessells H, Lue TF, McAninch JW. Penile length in the flaccid and erect states: guidelines for penile augmentation. The Journal of urology. 1996;156:995-7. PMID: 8709382
Mulhall JP, Schiff J, Guhring P. An analysis of the natural history of Peyronie’s disease. The Journal of urology. 2006;175:2115-8; discussion 2118. PMID: 16697815
Corona G, Rastrelli G, Di Pasquale G, et al. Endogenous Testosterone Levels and Cardiovascular Risk: Meta-Analysis of Observational Studies. The journal of sexual medicine. 2018;15:1260-1271. PMID: 30145097