Editorial Policy

The global baseline is the systematic review by Veale et al., BJU International (2015; 115(6):978–986), covering 15,521 clinically measured men. It is the only source used for percentile calculations, and its measurement protocol (bone-pressed, clinician-measured) is the protocol our guides teach.

Per-country averages are compiled from public aggregators (e.g. WorldData.info). They are not a single controlled dataset: the underlying sources mix clinician-measured studies with self-reported surveys, sample sizes vary enormously, and publication bias is likely. Every country page carries a data-quality box that states this next to the figure, with a reliability rating.

Percentiles are the cumulative distribution function of a normal distribution with the active baseline's mean and standard deviation, evaluated at your value (Abramowitz–Stegun error-function approximation, maximum error about 1.5 × 10⁻⁷). Displayed values use adaptive precision, so the tails never show a literal 0% or 100%.

Where a country provides no standard deviation, the erect SDs from the global review (1.66 cm length, 1.10 cm girth) are used as fallback, and the page says so. Country data exists for erect measurements only; flaccid mode always uses the global baseline. Size tiers are standard-deviation bands around the baseline mean, labeled by the percentile range each band covers.

If you find an error — a wrong figure, a miscalculation, a broken citation — report it to info@malesizeindex.com. We verify against the primary source, correct verified errors in the next deploy, and note the change on the affected page when the correction is material. We do not quietly edit statistics: the methodology page always reflects the currently deployed calculation.

The site is funded by a free email report and disclosed partner links (see the privacy & disclosure page). Partner links pay a commission at no extra cost to you. They are kept separate from the statistics: vendors have no input into data selection, calculations, rankings, or guide content, and no partner relationship is required to appear anywhere on this site.