How to play

The daily flow

• Read: a new real-world estimation question appears each day.
• Estimate: enter one number. The shortcuts multiply what you typed by a thousand, a million and so on.
• Calibrate: the result places your guess and the real answer on a magnitude ruler.

How scoring works

The score measures the gap between your guess and the answer in orders of magnitude, which is the difference between their base 10 logarithms. A gap under 0.05 scores 100. From there the score falls in a straight line and reaches 0 at a gap of 5, which is a factor of one hundred thousand.

Two consequences follow. Overshooting by ten times costs exactly as much as undershooting by ten times. And a guess of 1,000,000 for a real value of 600,000 still scores 97, because on this scale the two numbers are neighbours.

Entering large numbers

Type a small number and tap a shortcut: 7 then ×10⁹ gives seven billion. You can also type scientific notation directly, such as 7e9. A preview under the field spells your number out so you can catch a missing zero before you lock in.

Streaks and stats

Your streak grows by one for each consecutive day you play the daily question. All progress is stored in your browser, so it stays on the device you play on.