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. Here's where you find out whether that includes you.

Ten questions. Answer each one honestly before scrolling. The value of a test like this sits in the gap between your confidence and your accuracy, and you only get to see that gap if you commit first.

None of the questions are about a specific country, since those are the game's answers and I'm not giving them away. They're about the shape of the field: how it gets measured, who was sampled, what the big studies 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, against 45 percent who wanted to be larger. If you guessed anything above about 2 percent, take note: 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. It did not correlate with actual size. That's the 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. The effect is bigger in heavier men, since there is more fat pad to press through. Which 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 sit 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 small fraction of that, which is why this game's rotation is the size it is.

The three questions almost everyone gets wrong

From putting this to people, the same three trip nearly everybody, and each is wrong in an instructive direction.

Question 4, the 0.2 percent. People assume dissatisfaction runs both ways, as it does for nearly every other body-image concern. It doesn't here, and the one-directionality is the tell that this is about rank rather than fit.

Question 6, the shame not correlating with size. It violates the premise everyone has been operating under. If you got this one wrong it's worth sitting with, because it means the reassurance strategy most men reach for, measuring again more carefully in hope of a better number, cannot work by construction.

Question 8, the ruler press. Most people have never considered that the measurement has a technique at all. Once you have, every ranked chart you have ever seen becomes unreadable in a useful way.

Why a game rather than an article

You've just taken a test, which means you've just used the only mechanism that reliably updates a bad intuition: predict, then find out.

One test doesn't do much. A test a day for a month, each with a real figure and a real citation at the end, does. That's the difference between being told a fact and having been wrong about it, and being wrong is the part that sticks.

Which is the whole design of this site. Not a page of reassurance, but a daily, slightly humbling, ninety-second encounter with measured data.