What the published numbers actually say.
103,588 clinical measurements from 20+ peer-reviewed studies. Veale 2015 is the primary reference because it is the only meta-analysis to publish the standard deviations the percentile maths needs.
Mean 13.12 cm, SD 1.66 cm. 68% of measured men fall within the shaded ±1 SD band.
Mean 11.66 cm, SD 1.10 cm. Source: Veale et al. 2015, BJU International.
What sits behind every percentile.
The calculator uses Veale 2015 (13.12 ± 1.66 cm length, 11.66 ± 1.10 cm girth) because it is the only published study that provides the standard deviations percentile maths requires. The other studies validate the means.
Why Veale 2015 is the only study used for percentiles.
A percentile calculation requires both the mean and the standard deviation of the underlying distribution. Most published size studies report only the mean. Veale et al. 2015 is the largest meta-analysis to also publish standard deviations — 1.66 cm for length, 1.10 cm for girth — derived from 692 and 381 men respectively, measured under clinical conditions by professionals.
The other twenty studies in the database confirm the means within plus or minus one centimetre. They are shown in the table below to give the reader a sense of geographic spread and replication, not to drive the percentile maths.
Caveat. The database is weighted toward European and Middle-Eastern populations. North America has only three studies, China and Latin America one each, most of Africa one. Individual variation inside any population is much larger than the differences between populations.
All measurements in the underlying studies were taken by clinicians under standardised conditions. Self-reported surveys are excluded by design because they consistently overstate the mean by one to two centimetres.
Twenty studies, twenty countries, validated by replication.
| Study | Country | n | Erect length (cm) | Erect girth (cm) | Source |
|---|---|---|---|---|---|
| Belladelli et al. (2023) | Meta-analysis (24 countries) | 55,761 | 13.93 | Not reported | World J Men's Health |
| Mostafaei et al. (2025) | WHO regions (meta) | 36,883 | 13.84 | 11.91 | Urol Res Pract |
| Veale et al. (2015) | Meta-analysis | 15,521 | 13.12 ± 1.66 | 11.66 ± 1.10 | BJU International |
| Ponchietti et al. (2001) | Italy | 3,300 | 12.50 (str.) | 10.00 (flac.) | European Urology |
| Chen et al. (2024) | China | 5,000 | 12.42 ± 1.50 | Not reported | Asian J Andrology |
| Argentina Study (2022) | Argentina | 800 | 12.93 (str.) | Not reported | Asian J Andrology |
| Habous et al. (2015) | Middle East | 778 | Not reported | Not reported | Int J Impot Res |
| Park et al. (2016) | Korea | 201 | 14.60 | Not reported | Int J Urology |
| Singh et al. (2021) | India | 230 | 12.50 ± 1.80 | 11.20 ± 1.30 | J Andrology |
| Schneider et al. (2001) | Germany | 143 | 14.48 / 14.18 | Not reported | European Urology |
| Yafi et al. (2018) | USA | 274 | 13.10–15.50 | Not reported | Int J Impot Res |
| Aslan et al. (2011) | Turkey | 205 | 13.10 ± 1.70 | 12.40 ± 1.40 | Int J Impot Res |
| Ogunro et al. (2021) | Nigeria | 271 | 10.6 – 14.1 | Not reported | Pan Afr Med J |
| Al-Ali et al. (2017) | Iraq | 223 | 12.60 (str.) | Not reported | Arab J Urology |
| Wessells et al. (1996) | USA | 80 | 12.90 | 12.30 | Journal of Urology |
| Mehraban et al. (2007) | Iran | 1,500 | 11.58 | 8.66 | Int J Impot Res |
| Promodu et al. (2007) | India | 301 | 8.85 | 9.14 | Int J Impot Res |
| Global average (combined) | Worldwide | 103,588 | 13.12 ± 1.66 | 11.66 ± 1.10 | Combined |
All measurements taken by medical professionals, not self-reported.