Estimation Gym

One question a day, the same one for everyone. You do not have to be right — you have to be roughly right.

Play now

Takes about a minute. Nothing from an app store.

Free No account Works offline No ads Open source

📱 On iPhone or iPad

  1. Open this page in Safari.
  2. Tap Play now above.
  3. Tap the Share button — the square with an arrow pointing up, □↑.
  4. Scroll down and tap Add to Home Screen.
  5. Tap Add.

It has to be Safari. Chrome and Firefox on iPhone cannot add apps to the home screen — that is an Apple restriction, not a fault in the game.

🤖 On Android

  1. Open this page in Chrome.
  2. Tap Play now above.
  3. Tap the ⋮ menu, top right.
  4. Tap Install app, or Add to Home screen if that is what yours says.

Chrome may offer to install it by itself, in a bar along the bottom. Taking that offer does the same thing.

💻 On a computer

  1. Just tap Play now — it works in the browser.
  2. In Chrome or Edge you can also click the install icon in the address bar to keep it in its own window.
What you are installing

How many jellybeans fit in a one-litre jar?

Guess (jellybeans)
Go
Bullseye
2×
Close
10×
Ballpark
100×
Off

An example — not one of the real questions.

See it first
Fifty seconds, if you would rather see it than read about it.
▶ Seven-minute walkthrough
On YouTube — why powers of ten make a better puzzle

Why bother installing?

It opens like a normal app, with no browser bars, and it works offline — the questions travel with it, so it plays on a plane or underground.

Your streak and history stay on your own device. There is no account and no sign-up, and nothing about how you play leaves your phone.