DailyLoading
Fermi
Make your best educated guess. Fermi is an educated guess game of real numbers: how tall a million dollars in $100 bills stands, how many laps of a running track reach the bottom of the Mariana Trench. Make a guess, see the answer and the math, and keep going until one guess is 10 times off.
How to play Fermi
The rules, and the questions people ask.
How to play Fermi
The rules, and the questions people ask.
How to play
- 1Read the question: how many, how tall, how long, how much. Every answer is a real number, worked out from published figures.
- 2Make your best educated guess. 1.2 million, 3e6 and 12k all work, and the calculator button does the sums for you.
- 3Press Lock it in to see the real answer, how far off you were, and the napkin math and sources behind it.
- 4Stay within 10 times the answer, too high or too low, and the next question comes. Your score is how many you answer before the first miss.
Questions
What is the Fermi game?
Fermi is a free Fermi estimation game: questions you cannot know offhand but can reason your way to, like how tall a million dollars in $100 bills would stand. You make an educated guess, then see the real answer, the figures it comes from and the working that joins them.
What is the make an educated guess game?
A game of real numbers nobody knows offhand, so all you can do is make an educated guess: break the question into things you do know, how thick a bill is, how many seconds are in a day, and multiply your way to a number. Fermi Unlimited deals them from 2,667 questions with no daily limit, and the closer each guess lands, the longer your run lasts.
How is Fermi Unlimited different from the daily Fermi game?
The daily game deals a few questions a day. Fermi Unlimited has no daily limit: questions come one after another from 2,667 questions, getting harder as your streak grows, until one guess is more than 10 times off.
How does scoring work in Fermi?
Your score is your streak: how many questions in a row you answer within 10 times the real number. 10 times too high and 10 times too low are judged the same, and the first guess past that ends the run. Within 10% is a bullseye and within 2 times is close. Your best streak is kept on your own device.
Where do the answers come from?
Every answer is worked out from published figures: government statistics, manufacturer specifications, official records and reference works. Each figure was looked up independently, checked against the page it was quoted from, and dropped when sources disagreed. The arithmetic is done by code, and the reveal lists the figures and where they come from.
How do you get better at Fermi questions?
Break the question into pieces you can picture, estimate each to the nearest power of ten, and multiply. Being right about the number of zeros matters far more than the first digit. When one piece is guessed high and another low the errors partly cancel, which is why a chain of rough guesses usually lands closer than one wild guess.
More ways to play
Want a score against everyone else? Today's puzzle and the Global Gauntlet both put you on a leaderboard. More remakes: Songless Unlimited, Krillion, Bandle Unlimited, Size It Up, MapTap Unlimited, Poople Unlimited, Silverbrook and Songspot.