The claimed 11.5 cm is almost certainly too low. A 2021 study measured 14,597 men at Vietnamese andrology clinics and reported a median stretched length of 14.67 cm, more than three centimetres above the figure the map prints. Vietnam is the one country in this register where the internet understates rather than inflates.
The claim runs 3.17 cm below the measurement, and the two do not measure the same thing: the claim says erect, the study measured stretched. There is no accepted way to convert between them.
What was actually measured in Vietnam?
Fourteen thousand five hundred and ninety-seven men makes this the second-largest single dataset in the register, behind only the Chinese meta-analysis. It is clinician-measured, published in Andrology, and it reports a median rather than a mean, which is the more honest summary for a skewed sample. Nothing about the study explains why the map disagrees with it by 3.17 cm in the direction of smaller.
The sample is clinic-based, which is the standard caveat: men attending an andrology clinic are not a random draw from the population. Belladelli 2023 checked exactly this across 75 studies and found no significant difference between volunteer samples and urology patients, so the caveat is real but weak. It certainly does not account for a three-centimetre gap.
What makes Vietnam valuable is what it rules out. If the claimed figures were merely inflated by self-report, every error would run the same direction and you could subtract a constant. They do not. Vietnam is three centimetres low, Italy is between two incompatible studies, Australia is 2.41 cm below its own self-measured study, and Ecuador at the top of the map has no study at all. These are not measurements with a bias. They are numbers with no method.
How does that compare with the rest of the world?
The claim puts Vietnam 111th of 119 countries on the ranked list. Here is that number set against the figures that come with a method attached.
Figure
cm
What it is
The claim for Vietnam
11.50
Labelled erect. No method, no sample size, no reference.
Nguyen Hoai et al., Andrology
14.67
stretched, 14,597 men, 2021. The best located
measurement in Vietnam.
Clinically measured worldwide
13.12
Erect, 15,521 men. Veale 2015, the pooled clinical figure.
Pooled worldwide
13.93
Erect, 55,761 men. Belladelli 2023, 75 studies.
Pooled for Asia
11.74
Erect, 95 % confidence interval
10.18–13.29 cm
. Belladelli 2023.
That last interval is 3.11 cm wide,
for a whole continent, from the largest meta-analysis there is. The claimed map it sits
under spreads all 119 countries across
7.9 cm and prints every
country to one decimal place. Read those two sentences together and you have the
entire problem with penis size by country.
How many men does the claim cover?
14,597 measured → 36,000,000 described
14,597 men in Vietnam appear in the studies this register could locate. The claimed figure is applied to roughly 36,000,000 adult men: one measured man for every 2,466.
Where would you land in Vietnam?
Against the claimed figure, because that is the number people mean when they ask. It
is the weaker of the two numbers above, and the calculator says so. Everything is
computed in your browser and nothing you enter is stored or sent anywhere.
Travel advisory desk
Get your travel advisory
1,350,250,000men smaller
1,350,240,000men larger
50 of 100 men worldwide are larger than you.
L 13.6 cm
Estimated from the claimed world mean of 13.6 cm across ≈ 2,700,490,000 adult
men in 119 countries. You beat the claimed mean in 31 of them. The
claims are the internet's, not ours; we are grading them one by one.
See the audit.
What should you take from this?
Vietnam sits 111th of 119 on a map that contradicts the largest study ever conducted in the country. If you have seen the ranking used to say something about Vietnamese men, the ranking is not evidence, and the country's own data says the opposite.
The general rule this page illustrates: a national figure that disagrees with a 14,597-man clinical study is not a national figure. It is a number someone typed.
Nearby in the register
The nearest countries with an entry of their own here.
Nearer still, and with nothing to show: Cambodia, Laos, Thailand. Those
countries carry a claimed figure on every map and no located study behind it, so they
have no page here. The method page lists all of them.
Sources for this page
Nguyen Hoai et al., Andrology, 2021, n = 14,597. Clinician-measured at andrology clinics.
Study
Veale D et al. Am I normal? BJU International 2015; 115(6): 978–986. The pooled
clinical figures used throughout this site.
Belladelli F et al. Worldwide Temporal Trends in Penile Length. World J Mens Health
2023; 41(4). The regional pooled figures and confidence intervals.
The full reference list, the grading scheme and all 119 claims are on the
method and sources page.