VirMetra
Prototype 0.6.1
Evidence-based male anatomy statistics

How do you actually compare?

Private. Simple. Data-driven.

Based on published clinical measurements.

VirMetra Calculator

Enter your measurements

Use fully erect measurements following the VirMetra measurement protocol.

Your measurements stay on your device. They are calculated locally in your browser and are not stored or sent to VirMetra.

Your statistical profile

Your VirIndex

Estimated position under the current clinical reference model.

Length — cm
P—

Enter your measurements to calculate your percentile.

Circumference — cm
P—

Enter your measurements to calculate your percentile.

The data gap

We know less than you might think.

Most online comparisons rely on self-reported measurements, selected samples or visual impressions. Even high-quality clinical studies remain limited in size, geography and the variables they measure.

1

Self-reported

People measure differently. And sometimes inaccurately.

2

Selected samples

Online communities and adult media are not representative populations.

3

Limited clinical data

Better methodology, but smaller datasets and fewer dimensions.

Introducing

VirAtlas

A global, anonymous and progressively verified dataset of male anatomy.

Thousands of real people.
Standardised measurements.
One dataset.

Concept preview — your VirIndex is shown locally
Contributors —
Countries —
Verified measurements —
Visual contributions —
Length percentile
Circumference percentile
Length distributions Circumference distributions Flaccid ↔ erect variation Age groups Geographic comparisons Measurement verification Anonymous visual reference Future morphology analysis

The larger the dataset becomes, the better the answer becomes.

Built by its contributors. Useful to everyone.
Validation

Would you help build VirAtlas?

Nothing intimate is collected here. The live survey stores only your six answers and submission time — no measurements, photographs, name or email.

Question 1 of 6
Methodology & trust

Built on evidence, not guesses.

VirMetra uses published clinical research, a defined measurement protocol and an explicit statistical model to estimate where a measurement falls within the current reference distribution.

Reference data

Published clinical measurements

Standardised protocol

One defined way to measure

Transparent model

Assumptions and limitations made explicit

Privacy

Calculation stays on your device

VirIndex is an estimate, not a medical assessment. It describes anatomical measurements only and does not measure health, sexual function, attractiveness or personal worth.

VirMetra

Measure what we know.
Build what we don't.

Know where you stand. Help build what comes next.

Methodology-first Privacy-first Built to evolve
© 2026 VirMetra — Prototype 0.6.1
VirIndex scientific specification

How VirIndex works

VirIndex estimates the position of your measurements within a published clinical reference model. It evaluates erect length and erect circumference independently rather than combining them into a single overall score.

Current model VirIndex v1 · model-based estimated percentiles

Current reference model

VirIndex v1 is based on the nomograms published by Veale et al., who systematically reviewed professionally measured penile dimensions and constructed reference distributions using weighted means and pooled standard deviations.

Erect length 13.12 cm SD 1.66 cm · n = 692
Erect circumference 11.66 cm SD 1.10 cm · n = 381

The original nomograms modelled measurements with a normal distribution and used the cumulative normal distribution to derive percentiles. VirMetra follows the same statistical approach.

From measurement to percentile

Each measurement is first standardised relative to the reference mean and standard deviation, then mapped through the cumulative normal distribution.

Standard score z = (x − μ) / σ
Estimated percentile P = Φ(z)

A result such as P80 means the measurement is estimated to be higher than approximately 80% of the current reference distribution. It is a model-based estimate, not a direct count of every individual in a population. At the tails, VirMetra displays <P1 or >P99 rather than implying precision the current reference data cannot support.

Why use Veale as the current reference?

More recent meta-analyses include much larger bodies of evidence and report somewhat higher average erect lengths. Belladelli et al. report a pooled erect length of about 13.93 cm, but also very high between-study heterogeneity and evidence of variation with geography and publication year.

Mostafaei et al. report an erect-length mean of 13.84 cm and an erect-circumference mean of 11.91 cm. Their accompanying dispersion values are reported as standard errors, however, rather than individual-level standard deviations suitable for constructing a percentile distribution.

VirMetra therefore does not simply replace the Veale parameters with newer pooled means. The Veale model remains useful because it provides both the mean and the individual dispersion required for percentile estimation and was explicitly constructed as a nomogram. This choice may change as stronger reference data become available.

Measurement matters

A statistical reference is only meaningful when the input is measured in a reasonably comparable way. VirMetra therefore uses a defined protocol: fully erect, dorsal, bone-pressed length from the pubic bone to the tip of the glans, and fully erect circumference measured at mid-shaft.

Published methodological reviews show substantial variation between measurement techniques and identify standardisation as a major limitation of the existing literature.

Important limitations

  • The normal distribution is a statistical model. It should not be interpreted as proof that the true global distribution is perfectly Gaussian.
  • The reference samples are limited. Erect measurements in the original reference were much fewer than the total number of men included in the review.
  • Published studies are heterogeneous. Populations, measurement procedures, erection methods and study settings differ.
  • Self-measurement introduces uncertainty. The principal reference studies relied largely on measurements performed by healthcare professionals.
  • The model is not geographically adjusted. Current evidence is not strong or consistent enough for VirMetra to assign region-specific percentiles responsibly.
  • Some anatomies are less comparable with the model. Significant curvature, previous surgery, congenital differences or conditions affecting erection may reduce the relevance of the estimate.

What VirIndex does not measure

VirIndex describes anatomical measurements only. It does not measure or predict sexual health, erectile function, fertility, attractiveness, masculinity, sexual performance, compatibility or personal worth.

Privacy by design

The current VirIndex calculation runs locally in your browser. Your length and circumference are not sent to VirMetra, stored in a database or attached to an account.

If VirMetra later introduces voluntary contribution to VirAtlas, data contribution will remain a separate action requiring explicit consent.

Sources used for VirIndex v1

Veale et al. (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.

Greenstein et al. (2020) — Penile size in adult men—recommendations for clinical and research measurements.

Cakir et al. (2021) — Penile Length Measurement: Methodological Challenges and Recommendations, a Systematic Review.

Belladelli et al. (2023) — Worldwide Temporal Trends in Penile Length: A Systematic Review and Meta-Analysis.

Mostafaei et al. (2024) — A Systematic Review and Meta-Analysis of Penis Length and Circumference According to WHO Regions.

Habous et al. (2018) — Outcomes of variation in technique and variation in accuracy of measurement in penile length measurement.

Reference updates

Reference model: VirIndex v1. Scientific reference models are not permanent. If VirMetra adopts a stronger dataset in the future, the model version and methodology will be updated so users can understand what changed and why.

VirMetra measurement protocol

How to measure

VirIndex is only as useful as the measurement you enter. Small differences in technique can noticeably change the result, so use the same protocol every time.

Current VirIndex Fully erect length + fully erect mid-shaft circumference

Before you measure

Length Straight, rigid ruler
Circumference Flexible, non-stretch tape

Measure at full erection, in a comfortable private environment. For consistency, VirMetra recommends lying on your back.

You may measure yourself or, entirely at your discretion, ask another consenting adult you trust to take the measurements. Assisted measurement is not automatically more accurate: whoever measures should follow exactly the same protocol.

1

Erect length

Place the rigid ruler along the upper, dorsal side of the penis. Keep the ruler straight and gently press its base through the tissue at the pubic region until it reaches the pubic bone.

Measure in a straight line from the pubic bone to the furthest tip of the glans. Do not include foreskin extending beyond the glans, and do not measure from the visible skin junction alone.

Bone-pressed · dorsal side · pubic bone → glans tip
2

Erect circumference

Wrap the flexible, non-stretch tape around the middle of the shaft. Keep it level and perpendicular to the long axis of the penis.

The tape should rest against the skin without squeezing or compressing the tissue. Read the circumference where the tape meets itself.

Full erection · mid-shaft · no compression

If there is curvature

For a mild natural curve, gently align the shaft with the ruler as much as can be done comfortably and without force. VirMetra records a straight-line length: do not bend the ruler to follow the curve and never force the penis into a straighter position.

If a pronounced curvature prevents comfortable alignment, treat the resulting VirIndex as less comparable with the current reference model.

Enter what you actually measured

Do not round toward a preferred value and do not substitute a flaccid or stretched-flaccid measurement for the erect measurements requested by the calculator. You can enter centimetres or inches; VirMetra handles the conversion locally.

A note on comparability

The current reference data were collected primarily by trained professionals. A standardized self-measurement can still be useful, but some measurement uncertainty is unavoidable. Significant curvature, previous penile or pelvic surgery, erectile dysfunction, congenital anatomical differences or other conditions may also make the current reference model less applicable.

VirIndex is a statistical comparison, not a medical assessment.

Privacy

Your measurements are calculated locally in your browser and are not stored or sent to VirMetra. VirMetra does not currently ask you to upload photographs as part of the measurement process.