What percentile is a 6‑inch erect girth in clinical meta‑analyses of penis size?

1. Why the 15.24 cm number matters and how the nomogram was built

The 6‑inch measurement converts to 15.24 cm and should be compared to the erect‑circumference nomogram from Veale et al., which reported a pooled mean erect circumference of 11.66 cm with a pooled standard deviation (SD) of 1.10 cm and constructed percentile charts by simulating 20,000 observations from a normal distribution ^{[1] [2]}. Using those published parameters yields a Z‑score of (15.24 − 11.66)/1.10 ≈ 3.26 — corresponding to a percentile well above 99.9% in that model, meaning a 6‑inch erect girth would be extraordinarily rare in the Veale pooled sample ^{[1] [2]}.

2. How the math works and a sensitivity check

The nomogram method treats the pooled mean and pooled SD as defining a normal distribution and reads percentiles from that distribution — the Veale team explicitly simulated data to produce cumulative percentiles ^[2]. With the published mean and SD (11.66 ± 1.10 cm), a 15.24 cm circumference gives a Z ≈ 3.26, placing it in the top few thousandths of the population according to that model ^{[1] [2]}. Because erect‑girth data are sparse and interstudy variability exists, a sensitivity check using a larger SD (for example 2.0 cm to reflect higher heterogeneity) lowers the Z to ≈1.79 and moves the size to about the 96th percentile — still uncommon but not astronomically so; those alternative calculations reflect uncertainty acknowledged in the literature ^{[1] [2] [4]}.

3. Why uncertainty matters: small n and measurement heterogeneity

Veale et al. and subsequent meta‑analyses warn that erect‑circumference estimates are based on far fewer measured subjects than length measures — Veale pooled only a few hundred explicit erect‑girth measures (n≈231 for erect circumference in the review) and noted that erect measurements were much less common than flaccid or stretched measures, increasing uncertainty in the mean and SD used for percentile calculations ^{[1] [2]}. Other systematic reviews and meta‑analyses also flag lack of standardized measurement technique, interobserver variation and biases from self‑report or clinic settings as drivers of heterogeneity ^{[4] [5]}.

4. What other studies and reviews say and the range across analyses

Later and larger meta‑analyses emphasize regional differences and methodological inconsistency while producing similar central estimates for length; girth estimates vary and are reported with wider uncertainty, and some non‑peer summaries report maximum observed erect girths in the literature up to ~17.2 cm (6.75 inches), underscoring real between‑study spread ^{[4] [6] [7]}. The Veale nomogram remains the most cited reference for percentiles because it explicitly constructed percentile charts from pooled means and SDs, but the authors themselves and later reviewers recommend caution when reading extreme percentiles because of the sparse erect‑girth data ^{[1] [2] [4]}.

5. Bottom line with context and caveats

Under the commonly used Veale et al. pooled estimate (mean 11.66 cm, SD 1.10 cm) a 6‑inch (15.24 cm) erect circumference sits in the extreme upper tail — effectively well above the 99.9th percentile in that model ^{[1] [2]}. However, because erect‑girth sample sizes are small, measurement methods vary across studies, and meta‑analyses differ in how they handle heterogeneity, a conservative interpretation is warranted: 15.24 cm is uncommon to very rare in clinical meta‑analyses, but the precise percentile could be lower if true population variability is larger than the pooled SD reflects ^{[1] [4] [5]}.