Fermi GG

About Fermi GG

Fermi GG turns massive, seemingly impossible questions into manageable back-of-the-envelope calculations. Instead of exact numbers, you'll use everyday reasoning to estimate answers to large-scale prompts.

Each day brings a new set of three Fermi problems. You submit a guess, and the game scores you based on how close you are in terms of magnitude. The closer your guess is to the actual answer, the lower your multiplier—aim for 1× or as close to it as possible.

The scoring system uses multiplicative distance, so missing by a factor of two is much better than missing by a factor of ten. This rewards you for understanding the general scale rather than memorizing exact facts.

After each guess, Fermi GG provides a worked example that shows how you could have arrived at the answer using simple multiplication chains. This makes every round a learning opportunity, improving your estimation skills over time.

How to Play Fermi GG

Start a new daily game to receive three estimation prompts. For each prompt, think about the magnitude of the answer and type in your best guess. Submit your guess to see the actual answer, your score multiplier, and a breakdown of how a reasonable estimate could have been made. Complete all three prompts to see your average score for the day.

Tips for Fermi GG

Before entering digits, figure out the magnitude: is the answer in thousands, millions, or billions? Break big unknowns into smaller factors like population size, daily frequency, or days per year, and multiply them together. Always double-check the time period in the prompt—daily, monthly, annual, or all-time totals require different scales. Use the built-in calculator to keep your math organized, and don't stress about precision: a good neighborhood guess beats a precise wrong answer.