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Fermi

Fermi

fermi.gg

Three Fermi questions a day — estimate hard-to-know numbers with napkin math and get scored on how many times off you were.

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About Fermi

Fermi is a daily estimation puzzle built on Fermi estimation — the trick of chaining rough assumptions to get within an order of magnitude of a number nobody carries around in their head. Each day brings three questions, answered with gut instinct, napkin math, and the built-in calculator rather than a search engine. Scoring is a multiple of the real answer, so being 1.45× off beats being 10× off, and every reveal shows worked example math plus the distribution of how everyone else guessed.

Results are shareable, and players can submit questions of their own.

Pricing model: Free

Features

  • Three estimation questions every day
  • Scored as a multiple of the real answer, not a raw difference
  • Worked napkin math shown with each answer
  • A distribution of how everyone else guessed
  • Shareable daily score and share card
  • Submit your own question

FAQs

Common questions about Fermi

What is a Fermi question?
An estimation question you answer by reasoning from rough assumptions rather than looking it up — named after Enrico Fermi, who famously estimated the strength of an atomic blast from how far paper scraps flew.
How is my score calculated?
By how far off you were as a multiple of the real answer — landing within 1.5× scores far better than being 10× out.
Is Fermi free?
Yes — three questions a day, free in the browser.

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