Bone pressed vs non bone pressed: What the research says

The best evidence puts average erect penis length at 13.12 cm, or 5.16 inches, and the most standardized home method is a bone pressed measurement from the pubic bone to the tip along the top side of the shaft. There is no single average bone pressed vs non bone pressed penis length difference across studies because the gap changes with the suprapubic fat pad, and photo, hand, or semi erect estimates are far less reliable than a ruler and a soft tape.

Key takeaways

• A 2015 systematic review of 15,521 men found an average erect penis length of 13.12 cm, an average stretched flaccid length of 13.24 cm, and an average erect circumference of 11.66 cm.^[1]
• The classic 1996 Journal of Urology paper found that flaccid length is a poor predictor of erect length, which is why “how to measure penis” and “how to measure an erect penis” are not the same question.^[2]
• A 2021 review placed average erect length in modern datasets at roughly 5.1 to 5.5 inches, which is much closer to clinician measured values than to typical self reports.^[3]
• In the Massachusetts Male Aging Study, 52% of men age 40 to 70 reported some degree of erectile dysfunction, so incomplete rigidity is a common reason self measured erect length comes out low.^[7]
• No validated clinical formula can accurately estimate penis length or girth from a photo, even with hand comparison, because distance, angle, focal length, erection quality, and hand size all change the image.

Why penis measurement is easy to get wrong

Visible length and measured length are not the same thing. In urology, bone pressed means placing a rigid ruler on the dorsal side, the top of the shaft facing the belly, and pressing through the suprapubic fat pad until you feel the pubic bone. Non bone pressed uses the same top side line but starts at the skin at the base.^{[1] [2]}

The classic 1996 Journal of Urology paper by Wessells and colleagues found that ordinary flaccid length does not reliably predict erect length. That is why a casual flaccid measurement, or a photo of a semi erect penis, is not interchangeable with a true erect measurement taken under the same conditions.^[2]

A 2015 BJU International systematic review of 15,521 men reported an average clinician measured erect length of 13.12 cm and an average erect circumference of 11.66 cm. When men compare average erect penis length in bone pressed vs non bone pressed studies, they run into a basic problem: the review pooled studies that used slightly different dorsal starting points. A 2021 Journal of Sex and Marital Therapy review placed modern clinician measured erect length around 5.1 to 5.5 inches, which means the literature gives you a solid overall average, not a single accepted bone pressed erect length average or one universal non bone pressed value.^{[1] [3]}

How to measure length and girth the standard way

For penis length measurement, bone pressed vs non bone pressed uses the same ruler position but a different starting point. Bone pressed length starts at the pubic bone, non bone pressed length starts at the skin at the base, and the difference between them is person specific rather than a fixed average from published studies.^{[1] [2] [3]}

Bone pressed erect length

Bone pressed erect length, often shortened to BPEL, is measured with a rigid ruler placed on the dorsal side from the pubic bone to the tip of the glans. “Bone pressed” means enough pressure to feel bone through the suprapubic fat pad, not a hard shove, and this is the reference method most men mean when they ask what bone pressed is.^{[1] [2]}

Because the starting point is the bone, bone pressed erect length is the better choice for tracking change over time and for comparing yourself with studies that try to reduce fat pad error.^{[1] [2]}

Non bone pressed erect length

Non bone pressed erect length uses the same top side ruler position but starts at the skin at the base without compressing the fat pad. Record it separately because it reflects visible length, but it is not interchangeable with bone pressed length after weight change or when the suprapubic fat pad is large.^{[2] [3]}

Most large datasets do not publish both bone pressed and non bone pressed erect values in the same men, so there is no reliable average penis size conversion from one method to the other.^{[1] [3]}

Girth and circumference

Penis girth, or circumference, is the distance around the shaft, not the width across it. Measure only when fully erect, wrap a soft tape around the mid shaft, avoid the glans, repeat the reading three times, and average the numbers for a steadier result.^[1]

Mid shaft means the halfway point between the base and the start of the glans. For condom fit and for tracking change over time, circumference is the number around the shaft, not the width seen in a mirror.

Curved penises and photo estimates

If the shaft curves upward or sideways, a flexible tape or a string laid along the top contour can describe surface length along the curve, but a straight dorsal bone pressed ruler measurement remains the standard method for comparison with most published averages. By contrast, visual estimates from a photo, even with a hand reference, are not standardized medical methods at all. Clinical studies use direct measurement, not photo based guesses.^{[1] [2]}

That is why average erect penis length studies are useful and photo estimates are not. A hand, a camera angle, and a partially rigid shaft can all distort apparent size, so a photo cannot tell you your true bone pressed or non bone pressed measurement.^{[1] [2]}

Conditions that change measured length or visible size

Obesity, erection quality, and Peyronie’s disease can change visible or measured length. Size anxiety can distort perception of size, but it does not change the actual measurement.

Obesity and buried penis. Men with BMI in the obesity range, 30 kg per m2 or higher, often have a larger suprapubic fat pad, which reduces visible shaft and makes non bone pressed erect length look shorter even when underlying corporal length has not changed. This is why the bone pressed vs non bone pressed penis measurement difference can widen after weight gain, and why there is no single average correction that fits every man.

Erectile dysfunction. In the Massachusetts Male Aging Study, 52% of men age 40 to 70 reported some degree of erectile dysfunction. If rigidity is only partial, measuring erect penis length will underestimate your fully rigid number because the erectile bodies are not maximally filled.^[7]

Peyronie’s disease. Peyronie’s disease can cause curvature, indentation, and loss of straight line length, so a standard ruler may underread a curved shaft unless you follow the contour with a flexible tape or string.^[6]

Size anxiety. A 2021 counseling review noted that self reported penis size tends to run larger than clinician measured values. That is a reminder that “how does my penis measure up” is often more about perception than anatomy.^[3]

Signs your measurement method is off

Most bad self measurements come from the wrong starting point, a partial erection, or comparing yourself to a distorted photo.

• If repeated measurements during the same erection vary noticeably, your ruler position, start point, or erection quality may be inconsistent.
• If you are measuring from the underside, from the scrotum, or from where pubic hair starts, you are adding tissue that scientific studies do not count.
• If you expected a standard 0.5 inch or 1 inch gap between bone pressed and non bone pressed readings, your method may be off. Studies do not support one universal difference for all men.^{[1] [3]}
• If your photo looks much bigger when the camera is close to the tip, you are seeing perspective distortion, not more length.
• If non bone pressed length drops after weight gain but bone pressed length stays similar, the fat pad is the likely reason.
• If a semi erect measurement is much shorter than your fully erect measurement, that is normal.
• If an upward curve leaves air gaps between a rigid ruler and the shaft, use string or a flexible tape along the curve.
• If length seems suddenly shorter and you also notice pain, a new bend, weaker erections, or trouble with penetration, book a urology visit.

Myth vs fact

Myth: A hand in the photo lets you estimate size accurately

Fact: No validated medical formula can accurately estimate penis size from photo visual cues or hand comparison. Clinician studies use direct measurement with a ruler or tape, not photos, because lens distance, angle, and hand size vary too much.^{[1] [2]}

Myth: Scientific studies all use the exact same base to tip method

Fact: Published studies are not perfectly uniform. Some measure from the pubic bone and others from the pubopenile skin junction on the dorsal side, which is why the pooled 13.12 cm erect average cannot be labeled as a pure non bone pressed average or a pure bone pressed erect length average.^{[1] [2]}

Myth: Flaccid or semi erect size tells you your true erect length

Fact: Flaccid size is a poor predictor of erect size. In the classic Wessells paper, stretched length tracked erect length far better than ordinary flaccid length, which is why a locker room glance is not a valid proxy for a real erect measurement.^[2]

Myth: Bigger is what most partners care about most

Fact: Sexual satisfaction is not determined by penis length alone. Erection quality, comfort, partner communication, and treatment of conditions such as erectile dysfunction or Peyronie’s disease are usually more clinically relevant than size comparisons.

What to do if you want a number you can trust

A repeatable measurement taken the same way three times is more useful than any single photo or guess.

1. Step 1: Measure erect length the same way every time. Stand upright. Place a rigid ruler on the top side. For bone pressed erect length, start at the pubic bone. For non bone pressed erect length, start at the skin at the base. Read the number at the tip of the glans.
2. Step 2: Measure girth separately. Wrap a soft tape around the mid shaft only when fully erect. Record the measurement three times and average it.
3. Step 3: Compare only to numbers measured the same way. Do not compare bone pressed erect length to non bone pressed erect length, and do not compare your ruler to a photo, porn frame, mirror angle, or hand reference. If a new curve, pain, or erection loss appears, see a urologist rather than assuming your penis has permanently shrunk.

If worries about size come with weaker erections, low libido, infertility, or fatigue, Veedma can help separate measurement anxiety from a real medical issue. Veedma offers a thorough diagnostic workup across the U.S., including review of existing results or morning testing from 07:00 to 11:00 with Total Testosterone by LC-MS/MS, Free Testosterone by Equilibrium Dialysis with LC-MS/MS, LH, FSH, Estradiol, CBC, Comprehensive Metabolic Panel, Vitamin D, PSA for men over 40, and Insulin when BMI is above 25. Because male hypogonadism requires persistent symptoms plus biochemical evidence, Veedma uses 350 ng/dL for total testosterone and 100 pg/mL for free testosterone as decision thresholds when symptoms persist. When LH is below 8 mIU/mL and the pattern fits secondary or functional hypogonadism, Enclomiphene is the first line option. The Enclomiphene + Tadalafil combination tablet may be used when erection or urinary symptoms are also present, with follow up after the first month and then every 6 months through ongoing monitoring by licensed providers.

The bottom line

You cannot accurately estimate penis size from a photo. If you want the standard number, measure a fully erect penis on the top side from the pubic bone to the tip for bone pressed length, record non bone pressed length separately, and measure mid shaft girth with a soft tape.

References

1. 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
2. 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
3. King BM. Average-Size Erect Penis: Fiction, Fact, and the Need for Counseling. Journal of sex & marital therapy. 2021;47:80-89. PMID: 32666897
4. Prause N, Park J, Leung S, et al. Women’s Preferences for Penis Size: A New Research Method Using Selection among 3D Models. PloS one. 2015;10:e0133079. PMID: 26332467
5. Promodu K, Shanmughadas KV, Bhat S, et al. Penile length and circumference: an Indian study. International journal of impotence research. 2007;19:558-63. PMID: 17568760
6. Tsambarlis P, Levine LA. Nonsurgical management of Peyronie’s disease. Nature reviews. Urology. 2019;16:172-186. PMID: 30397330
7. Feldman HA, Goldstein I, Hatzichristou DG, et al. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. The Journal of urology. 1994;151:54-61. PMID: 8254833