What the published data actually says

The standard reference, Veale et al. (2015), BJU International, puts mean erect length at 13.12 cm and stretched flaccid length at 13.24 cm, from up to 15,521 men. Every measurement was taken by a health professional using a standard procedure, not reported by the participant.

That single criterion is what separates it from essentially everything else circulating online.

The figures

The last column matters: the erect figures rest on hundreds of men, not thousands, and the authors list "relatively few erect measurements" taken in a clinical setting as a limitation.

Two things about this table surprise people every time.

The first is that erect length and stretched flaccid length are almost identical. That is not a coincidence - it is why stretched flaccid is used clinically as a proxy, since it is far easier to standardise in a consulting room.

The second is simply that the erect figure is around 13 cm. The number most people carry in their head is larger, and the reason for that gap is well documented.

The distribution is narrow

The paper's central contribution is a set of nomograms - percentile curves rather than single averages - and their shape is the useful part.

The practical consequence: the range containing most people is only about three centimetres wide. Small absolute differences move you a long way through the percentiles, and large differences are genuinely uncommon in both directions.

It also means the difference between a careful measurement and a sloppy one - which is larger than it sounds - can be worth ten or more percentile points on its own. Measurement error is not a small effect against a distribution this tight.

What a newer pooled estimate adds

A larger review has since appeared: Belladelli et al. (2023), World Journal of Men's Health, pooled 75 studies and 55,761 men and reported a mean erect length of 13.93 cm. It also reported that erect length rose 24% over 29 years after adjustment, a finding the authors say needs its causes investigated. Its pool admits samples of 10 or more men, against Veale's minimum of 50, so it is wider but noisier - and Veale remains the usual reference for a clinician-measured figure.

What the paper does not claim

It does not report ethnic differences - the authors state the data were insufficient to draw conclusions, which has not stopped the paper being cited for exactly that.

It does report a correlation with height, r = 0.2 to 0.6 for stretched or erect length, which is too weak to predict any one person's figure. Foot size has even less behind it: Shah and Christopher (2002), BJU International, measured 104 men and found no statistically significant correlation between shoe size and stretched length.

And it does not say anything about anybody's satisfaction with anything. It is a set of measurements. Whether a given number reads well to a given person is a different question, and people who ask a human judge mostly turn out to be asking that one.

Reading your own number against it

Measure the way the method describes, take the median of three, and compare to the nomograms rather than to the mean. A percentile is more informative than a distance from average, particularly on a distribution this narrow - the same logic that makes a rating tool's public distribution more useful than its raw score.

Then hold it loosely. A percentile is a fact about a distribution of measurements. It is not an assessment, and if an assessment is what you were after, that is a different kind of judgement entirely - the sort of thing Rate Cock produces - and it is not derived from a length in centimetres at all. An image model cannot see centimetres in the first place; what it reads from a photograph is proportion, not size.