What are the documented percentiles (5th, 50th, 95th) for erect penis length in clinician‑measured meta‑analyses?

1. Why the question matters and which studies count as “clinician‑measured”

The most reliable meta-analyses on penis size restrict to measurements taken by health professionals using standard protocols, because self‑reported values are systematically biased; Veale and colleagues explicitly required clinician measurements and a minimum sample size to construct their nomograms ^[1]. A later WHO‑regions meta‑analysis similarly limited inclusion to studies where healthcare professionals measured size, improving comparability across populations ^[4].

2. The Veale nomogram: the practical percentile estimates clinicians use

Veale et al. pooled studies to produce nomograms for flaccid, stretched and erect penile length and reported an erect mean of 13.12 cm with a pooled SD of 1.66 (n for erect measurements = 692), then simulated a normal distribution to generate percentiles ^{[1] [2]}. Modeling those numbers with standard normal z‑scores yields approximate erect percentiles: 5th ≈ 10.4 cm, 50th = 13.12 cm, and 95th ≈ 15.9 cm — a calculation based on the pooled mean and SD the authors documented ^{[1] [2]}.

3. Newer meta‑analyses give similar central tendencies but lack dispersion for percentiles

A 2024/2025 systematic review and meta‑analysis covering WHO regions reported a pooled mean erect length of 13.84 cm across 5,669 men, but the excerpted text gives that value as a mean with standard error (SE = 0.94) rather than a pooled SD needed to compute percentiles directly from a normal model ^{[3] [4]}. Without a reported SD or access to the underlying study‑level variances, exact 5th and 95th percentile estimates cannot responsibly be calculated from that paper alone ^{[3] [4]}.

4. Measurement caveats and why nomogram‑derived percentiles are approximations

Meta‑analysts typically assume an approximately normal distribution and may simulate populations (as Veale did) to produce percentile curves, but erect measures are fewer and more heterogeneous across studies than flaccid or stretched measures, producing greater uncertainty in tails of the distribution ^{[2] [1]}. Interobserver variability, differing protocols for inducing or measuring erection, and small sample counts for erect measurements (Veale n = 692) mean percentile estimates—especially extreme percentiles—carry measurement and sampling uncertainty ^{[2] [1] [5]}.

5. Reconciling different results and what can be stated with confidence

Across clinician‑measured meta‑analyses the central tendency for erect penile length clusters around 13–14 cm, and the best public nomogram data give a median of ~13.1 cm with approximate 5th and 95th percentiles of ~10.4 cm and ~15.9 cm respectively using the pooled SD from Veale et al. ^{[1] [2]}. Recent larger meta‑analytic means (e.g., 13.84 cm) corroborate that central band but do not, in the cited excerpts, provide the dispersion metrics needed to update percentile calculations ^{[3] [4]}.

6. Alternative viewpoints, implicit agendas and limitations of available reporting

Some studies infer erect length from stretched flaccid measures (often strongly correlated) to compensate for few direct erect measurements, and the stretched:erect ratio is reported as close to 0.98 in some analyses—an argument used to justify using stretched measures when erect data are sparse ^[5]. Reporting biases, regional sampling differences, and the possibility that some datasets overrepresent certain ancestries or age groups are acknowledged caveats; the included meta-analyses themselves warn against overinterpreting small subgroup differences or attempting to ascribe racial patterns from these pooled data ^{[1] [3]}. The present summary is limited to the specific clinician‑measured meta-analyses and the statistics they publish; where dispersion parameters were not provided in the available excerpts, exact percentile computation was not performed.