The Fermi game at fermi.gg gives players three estimation questions a day and scores each guess as a multiple of the real answer. It’s free with no account, and it comes from the studio behind Spotle.
I played puzzle No. 85 on October 19 and finished at 1.01×, which the site put in the top 1%. Do you need to be good at math? Not really. I didn’t need more than grade-school arithmetic. The scoring and the name are what’s worth explaining, because several sites call their game Fermi and they aren’t the same game.
How Does the Fermi Game Work?
Each day the Fermi game shows three questions about numbers nobody carries in their head, such as how many sandwiches a chain sells in a day. There’s one guess per question, typed into a box with the unit already printed inside it, and then you tap Lock it in.
The answer appears straight away. A card puts your guess next to the real number, shows the multiple, and says how many players you beat. Below it, a bar chart shows how everyone else guessed, with a marker for you.
Some questions come with a photo you can tap to enlarge. The one about NASA’s Curiosity rover had one.
How Is the Fermi Game Scored?
Fermi scores each guess by how many times off it was, as a multiple of the real answer, so an exact guess is 1× and lower is better. The score for the day is the average of the three.
On the home page, a demo guess of 1,245 against an answer of 1,800 scores 1.45×, labeled Too Low. My own numbers follow the same rule. I guessed 17,000 on a question whose answer was 17,600, which is 1.035 and showed as 1.04×.
My other two guesses scored 1.00×. The average came to 1.01×.
Is that scale harsh? Not on small slips. A miss of about 4% barely moves the score, while ten times off gives 10×.
When I looked, the top three on the leaderboard all sat at 1.02×, so the race is in the second decimal.
What Do Napkin Math and the Calculator Do?
Napkin Math is a panel under each answer that shows how the number could have been reached, with the figures and a source line. The calculator icon beside the guess box opens a scratch pad and a basic calculator for your own sums.
Here’s one from puzzle No. 85. A million euros in €100 notes is 10,000 notes, and at about a gram each that’s roughly 10 kilograms. The source line named the Austrian central bank’s banknote specifications.
The scratch pad has a notes area on one side and the keys on the other: clear, backspace, percent, the four operations, a pi key and a decimal point.
The site’s how-to says “No Googling”, and players take that seriously. A September 2026 thread on r/northernlion, with 148 upvotes, was a rant against people who look the answers up.
“I don’t think I will ever understand the thinking behind cheating in a intelligence-based game”
– r/northernlion, September 2026 (79 upvotes)
Which Fermi Game Is Which?
At least four sites run a Fermi estimation game under that name, and only fermi.gg uses the three-question daily format with one guess each. The others are separate games with their own rules.
| Site | Format | Scoring |
|---|---|---|
| fermi.gg | Three daily questions, one guess each | Multiple of the answer, lower is better |
| Daily (playdaily.org) | Endless questions in one run | How many you survive in a row by landing within 10 times the answer |
| Tradermath | Eight questions of 60 seconds each by default | A low-high range, up to 200 points a question; harder levels need a paid plan |
| Quantable | Timed or fixed-length rounds, math or real-world questions | 1 point for a perfect estimate, partial credit otherwise |
Daily’s own page says it isn’t the same game as fermi.gg. Quantable’s start page says trading firms ask Fermi-style questions in interviews, which explains its timed rounds. Anyone after a daily habit wants fermi.gg, the one that resets at midnight.
What Are the Archive, Leaderboard and Streaks?
The Fermi archive lists every puzzle since the first, 85 of them as of October 19, and lets you replay any day. Joining the leaderboard needs an account. The game itself doesn’t.
Puzzles run newest first, 25 to a page, with filters for All, Completed and To play. A score appears next to each day you’ve played. Even signed out, my results page showed an average score, a day streak, a best score and a count of puzzles played.
Leaderboard tabs cover Today, 7 days, All time, Streaks and Badges. Playlin’s weekly chart of daily games had Fermi at No. 32 for the week of October 19, up eight places.
Fermi Game FAQ
Is the Fermi game free?
I played the daily puzzle without an account or a payment screen, so the daily game is free. The only sign-in prompt I saw was for the leaderboard.
Can you use a calculator in the Fermi game?
Yes. The calculator icon next to the guess box opens a scratch pad and calculator, and the site’s FAQ says one is built in for exactly this.
When does the new Fermi puzzle come out?
A new puzzle goes up every day at midnight Eastern Time, according to the site’s FAQ. The results page counts down to it.
Where can you find today’s Fermi answers?
No outside source is needed. The answer and the worked math appear as soon as a guess is locked in. Past puzzles stay in the archive, so they can still be played fresh.
What is a Fermi question?
A Fermi question asks for a number that can’t easily be looked up and gets solved with rough, rounded steps. The site credits the idea to physicist Enrico Fermi and says he estimated an atomic bomb’s strength from how far scraps of paper flew.
Who makes the Fermi game?
Flatwhite Studios, a small studio that also makes Spotle, Spotle Movies, Harmonies and Crosstune. Fermi’s results page links to Spotle, Spotle Movies and Crosstune.
