How many people are packed into every square kilometre of a country? Density Guess is a free daily geography game that asks exactly that. You get five mystery countries a day and one estimate each: how crowded is it, in people per square kilometre? The closer you land, the more points you keep.

Population density is the geography stat that surprises everyone. Bangladesh packs over 1,000 people into each square kilometre while Australia and Canada barely reach four. Monaco tops 19,000; Mongolia sits near two. Because the answers span four orders of magnitude, Density Guess scores you on a fair log-ratio scale, so being twice off costs the same whether a country runs at 5 or 500 per square kilometre.

Everyone in the world gets the same five countries each day, so you can compare scores and share a spoiler-free emoji card. Keep a daily streak going, or switch to the endless mode and see how long you can survive. No sign-up, no app, plays right in your browser.

Play Density Guess

How to play

You are shown a country’s flag, name and continent. No population, no size hints.
Estimate its population density in people per square kilometre. Type a number (for example 60, 441 or 19k) or drag the log-scale slider.
Lock in your guess. The real density counts up on a log-scale bar right next to yours, with an arrow showing how many times too high or too low you were.
Score up to 1,000 points per country. Land within 10% for a bullseye.
Play all five, then copy your emoji score card and share it. New countries every day at midnight UTC.

Game modes

Daily. Five mystery countries, drawn one from each density band (from wide-open to jam-packed) so every day mixes an easy read with a tricky one. One estimate each, scored out of 5,000. The same five countries for every player worldwide, so your emoji card is worth bragging about.

Endless. A fresh random country every round. Stay within 2× of the true density to keep your streak alive; you have three lives. How far can you run?

The geography behind it

Population density (people per square kilometre) is population divided by land area, and it rarely matches your intuition. Big countries can be nearly empty: Russia averages about eight people per square kilometre, Canada around four. Small ones can be astonishingly crowded: Singapore clears 8,000 and Monaco more than 19,000. Even similar-sized neighbours diverge wildly, which is what makes each guess a real puzzle.

Because those figures range from roughly 2 to nearly 20,000 per square kilometre, Density Guess measures accuracy on a log-ratio scale rather than a flat percentage. Your error is the base-10 logarithm of guess divided by actual, so a 2× miss is penalised the same at any scale. Points are 1,000 times accuracy squared: exact is 1,000, within 10% is about 919, twice off is roughly 489, and ten times off scores zero. It is the same fair method behind our Population Guess game.

Density figures and flags are bundled into the game at build time from Mappr’s open country dataset and the CC0 flag-icons project, so the game makes no third-party calls and runs entirely in your browser.

Frequently asked questions

Is it the same puzzle for everyone today?

Yes. The day’s five countries are seeded from the current UTC date, so every player worldwide gets exactly the same challenge. That is what makes comparing scores and sharing your emoji card fun. New countries appear at midnight UTC.

What exactly am I guessing?

Population density: the number of people per square kilometre. You can type a plain number, add a k for thousands (handy for city-states), or use the log-scale slider.

How is my score calculated?

On a log-ratio scale, so being twice off costs the same whether a country is sparse or crowded. Exact scores 1,000 points, within 10% about 919, twice off around 489, and ten times off scores zero. Five countries make a 5,000-point daily maximum.

What is the difference from Population Guess?

Population Guess asks for a country’s total population; Density Guess asks how tightly those people are packed per square kilometre. Density is far less intuitive, so it plays fresh even if you know your populations.

Do I need an account or an app?

No. Density Guess is free, needs no sign-up, and plays entirely in your browser on phone or desktop. Your streak and stats are saved locally on your device.

Where does the data come from?

Population density figures come from Mappr’s open country dataset, and the flags are from the public-domain (CC0) flag-icons project. Everything is bundled at build time, so there is no tracking and no third-party data calls.

More Mappr geography games

Population Guess – estimate a country’s total population.
Higher or Lower Geography – which country ranks higher on population, area, GDP or density?
World Rank – put five countries in order by a hidden stat.
Closest Country – the daily proximity guessing game.
Browse every Mappr tool and game on the apps page.