How well do you actually know this data? Ten questions.

Everything else on this site argues that almost everyone's sense of this subject is badly calibrated. This piece is where you find out whether that includes you.

Ten questions. Answer each one honestly before you scroll — the whole value of a test like this is in the gap between your confidence and your accuracy, and you only get to observe that gap if you commit first.

None of these questions are about a specific country, because those are the game's answers and I am not giving them away. They are about the shape of the field: how it is measured, who was sampled, and what the big studies actually found.

The questions

Write down or hold your answer for each. No looking.

1. 1.What is the pooled worldwide average stretched length, to the nearest centimetre?
2. 2.Roughly how many men were included in the largest meta-analysis in this field?
3. 3.In the 52,031-person Lever survey, what percentage of women said they were satisfied with their partner's size?
4. 4.In that same survey, what percentage of men said they wished they were smaller?
5. 5.Of 67 men who presented at a clinic requesting surgical lengthening, how many turned out to have an anatomically short penis?
6. 6.Does a validated scale of penis-size shame correlate with actual penis size? Yes or no.
7. 7.How much length does penile enhancement surgery typically add, according to the major systematic review?
8. 8.Pressing the ruler into the pubic bone versus not — roughly how much does that change the recorded figure?
9. 9.In the 3D-model study, did women's preference for a long-term partner come out higher or lower than for a one-time partner?
10. 10.Roughly how many countries have a traceable, clinician-measured national figure for stretched length?

The answers

1. About 13 cm. Belladelli's 2023 review of 75 studies and 55,761 men puts pooled stretched length at 12.93 cm. Veale's 2015 review of up to 15,521 men puts it at 13.24 cm, with erect length at 13.12 cm. Two teams, two decades, the same neighbourhood.

2. 55,761. That is the Belladelli figure, drawn from studies published between 1942 and 2021.

3. 85 percent. Against 55 percent of men satisfied with their own. The thirty-point gap is the most-quoted statistic in this field and it deserves to be.

4. 0.2 percent. Two men in a thousand. Compared with 45 percent who wanted to be larger. If you guessed anything above about 2 percent, notice that — the intuition that this is a two-sided preference is very common and very wrong.

5. None of them. Mondaini's 2002 study measured all 67 and found not one who could be classified as short, and none with any anatomical abnormality.

6. No. Veale's Beliefs About Penis Size scale correlated with depression, anxiety, social anxiety, body-image quality of life and erectile function — and not with actual size. This is the single most important finding on this page.

7. One to two centimetres. That is the range Vardi's systematic review reports, alongside frequently reported complications and patient satisfaction the review describes as disappointing.

8. About a centimetre, sometimes more. And the effect is larger in heavier men, because there is more fat pad to press through. This is why methodology sections matter more than country names.

9. Lower. Slightly, but consistently — about 16.0 cm for a long-term partner against 16.3 cm for a one-time partner. Both above average; the direction of the difference is the interesting part.

10. Roughly two dozen. Not 190. The viral world map shades every country on Earth; the literature supports a fraction of that, which is why this game's rotation is the size it is.

The three questions almost everyone gets wrong

In my experience of putting this to people, the same three trip nearly everybody, and each one is wrong in an instructive direction.

Question 4 — the 0.2 percent — because people assume dissatisfaction runs both ways, as it does for almost every other body-image concern. It does not. The one-directionality is the tell that this is about rank rather than about fit.

Question 6 — the shame not correlating with size — because it violates the entire premise everyone has been operating under. If you got this wrong, it is worth sitting with, because it implies that the reassurance strategy most men reach for (measure again, more carefully, hoping for a better number) cannot work by construction.

Question 8 — the ruler press — because most people have never once considered that the measurement has a technique. And once you have, every ranked chart you have ever seen becomes unreadable in a useful way.

Why a game rather than an article

You have just done a test, which means you have just experienced the only mechanism that reliably updates a bad intuition: predict, then find out.

One test does not do much. A test a day, for a month, with a real figure and a real citation at the end of each, does something. It is the difference between being told a fact and having been wrong about it — and having been wrong is what actually sticks.

That is the entire design of this site. Not a page of reassurance. A daily, slightly humbling, ninety-second confrontation with measured data.