How do you play the Higher or Lower Game?
Two cards on a random topic: the first shows its number, the second hides it. Guess whether the hidden number is higher or lower. A right guess brings a new pair on a different topic; one wrong guess ends the game. Your result is your streak, the number of right guesses in a row.
There are 13 topics: 8 about countries, 3 about animals and 2 about chemical elements. You don't pick one; each question names its topic above the cards. Use the buttons, or the up and down arrow keys.
Where do the Higher or Lower numbers come from?
Every figure comes from a public source, named under the cards and checked on 31 October 2026: the World Bank for countries, AnAge (the Animal Ageing and Longevity Database) for animals, and PubChem, from the US National Library of Medicine, for elements. No figure is estimated or made up for the game.
| Topic | Source | Cards | From … to |
|---|---|---|---|
| Population | World Bank, 2025 | 160 | Djibouti (1.18 million) to India (1.46 billion) |
| Area | World Bank, 2024 | 157 | Singapore (736 km²) to Russia (17.1 million km²) |
| Size of the economy | World Bank, 2025 | 151 | Timor-Leste ($1.9 billion) to United States ($30.8 trillion) |
| Income per person | World Bank, 2025 | 151 | Burundi ($234) to Ireland ($131,592) |
| Life expectancy | World Bank, 2024 | 160 | Nigeria (54.6 years) to Hong Kong (85.4 years) |
| Births per woman | World Bank, 2024 | 160 | South Korea (0.75) to Chad (6.03) |
| Forest cover | World Bank, 2024 | 155 | Libya (0.12%) to Gabon (91.4%) |
| Internet use | World Bank, 2024 | 148 | Burundi (8.6%) to United Arab Emirates (100%) |
| Animal lifespan | AnAge, Build 15 | 154 | Brown rat (3.8 years) to Greenland shark (392 years) |
| Animal weight | AnAge, Build 15 | 148 | Ruby-throated hummingbird (3.1 g) to Blue whale (136 tonnes) |
| Pregnancy length | AnAge, Build 15 | 119 | African clawed frog (2 days) to African bush elephant (670 days) |
| Melting point | PubChem, NIH | 39 | Hydrogen (−259 °C) to Tungsten (3,422 °C) |
| Density | PubChem, NIH | 30 | Lithium (0.53 g/cm³) to Osmium (22.6 g/cm³) |
The country topics cover every place the World Bank lists with at least a million people, a few territories such as Hong Kong and Puerto Rico included. Each topic uses one year for all its cards, the latest with a figure for at least 90% of the places, so no country is compared with an older count of its neighbor; a place without a figure that year sits that topic out. Area includes lakes and rivers, GDP is in US dollars of that year, and forest cover under 0.1% of the land is left out.
The animal lifespans are records, not typical lives: AnAge's longest known lifespan for each animal, kept only where the database rates its data acceptable or high. That is why a human card says 122.5 years. Weights are typical adult weights, and pregnancy length is gestation for mammals and incubation for animals that lay eggs. Melting points are at everyday air pressure, and density is given only for elements that are solid or liquid at room temperature.
How does the Higher or Lower Game pick each question?
At random, within limits. The topic is any of the 13 except the one just asked, and the pair is two of its cards you haven't been shown together this game, never within 10% of each other, so no answer hangs on a rounding or a newer estimate. Which card is shown and which is hidden is a coin flip.
The pairs close in as your streak grows. Line a topic's cards up from smallest to largest: for your first 5 guesses the two cards are at least 40% of the line apart. From a streak of 5 they are 15% to 50% apart, and from 10 no more than 20%, so a long streak needs real knowledge. Spacing by place in the line works the same for animal weights, from 3.1 g to 136 tonnes, as for life expectancy, from 54.6 years to 85.4 years.
What is a good Higher or Lower streak?
Every guess is a choice of two, so guessing alone keeps a streak going half the time. The chance of guessing your way to a streak halves with each card:
| Streak | Chance by guessing alone |
|---|---|
| 5 | 1 in 32 |
| 10 | 1 in 1,024 |
| 15 | 1 in 32,768 |
| 20 | 1 in 1,048,576 |
Early pairs are far apart, so a first streak of five says little; past 10, when the numbers are close, each right answer means more. To see how well you know what you know, try the Overconfidence Test, or judge numbers by eye in the Estimation Game.