Methodology
Where the numbers come from, and how every comparison is computed.
The global baseline: Veale et al. (2015)
Veale D, 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 Int. 2015;115(6):978–986.
This systematic review pooled clinically measured data from up to 15,521 men across multiple studies, measured by health professionals with a standardized bone-pressed technique rather than self-reported. That sample size is what makes the resulting nomograms the reference baseline for global comparisons.
- Erect length
- 13.12 cm ± 1.66 SD
- Erect girth
- 11.66 cm ± 1.10 SD
- Flaccid length
- 9.16 cm ± 1.57 SD
- Flaccid girth
- 9.31 cm ± 0.90 SD
Country compilation data
The world map and country baselines cover 134 countries and are compiled from public aggregators (e.g. WorldData.info).
Reliability caveat: these figures mix self-reported surveys, small samples and inconsistent measurement protocols. They are not peer-reviewed and vary widely in quality. Treat every country-level number as an indicative estimate, not a clinical reference.
Standard deviation fallback
The country compilations publish means only. To place a country average on a distribution, the app falls back to the erect standard deviations from the Veale review: 1.66 cm for length and 1.10 cm for girth.
Where a country ever ships its own SD (the dataset supports optional per-country SD fields), that value is used instead. Flaccid comparisons always use the global baseline, because country data exists for erect measurements only.
Size tiers
Values are classified into six standard-deviation bands around the active baseline mean. The population shares are exact normal-distribution band probabilities:
- Microbelow −2 SD2.28% · ≈ 23 are smaller
- Modest−2 to −1 SD13.59% · ≈ 136 are smaller
- Average−1 to +1 SD68.27% · ≈ 683 land here
- Large+1 to +2 SD13.59% · ≈ 136 are larger
- Huge+2 to +3 SD2.14% · Only ≈ 21 are larger
- Elite / Massiveabove +3 SD0.13% · Only ≈ 1 is larger
Percentile math
A percentile is the cumulative distribution function of the baseline normal distribution evaluated at your value, the share of the population below it. The CDF uses the Abramowitz–Stegun 7.1.26 error function approximation (maximum error ≈ 1.5×10⁻⁷).
Displayed percentiles use adaptive precision: near the tails you see two decimals, and the extremes collapse to "< 0.1%" / "> 99.9%", so the app never claims a literal 0% or 100%.