Estimation Sniper: free Fermi estimation game, guess smart

What is Estimation Sniper?

Eight Fermi questions: seconds in a year, litres in an Olympic pool, heartbeats in a life, piano tuners in a city. Break each one into steps you can guess, take your shot, then see the reference value and the reasoning.

Estimation Sniper is a free Fermi estimation game. Each question is too big to know offhand, like how many seconds are in a year, how many litres an Olympic pool holds or how many times a heart beats in a lifetime, but each can be broken into small steps you can guess and multiply.

Type or slide your estimate and take your shot. Points come from the log-distance to the reference value: being ten times too high costs the same as being ten times too low. Land inside the target band for a bonus and a harder level. After each shot you see the reference value, phrased “about”, with the steps and where the figures come from.

At a glance

Category

IQMaxxing

Difficulty

Medium

Play time

3–5 min

Price

Free, in your browser, sign-up optional

How to play

Break it down

Split the question into numbers you can guess: hours, people, metres.

Take your shot

Type a number (3000, 2.5 million, 4e9), slide, or use ×10 and ÷10.

Log-distance score

Points fall with how many powers of ten you are off, high or low the same.

Hit the band

Inside the target band: +50 and a harder level with a tighter band.

Scoring

Up to 100 points per shot for closeness: zero at about 30 times off. Ten times too high costs the same as ten times too low.

+50 inside the target band, which tightens as you level up; ×0.7 if you used the hint. Eight shots per run.

What it trains

Estimation

Breaking a big unknown into small steps you can guess.

Number sense

Getting the power of ten right before the digits.

Reasoning

Checking each step against things you already know.

Strategy and tips

Split it up

Turn one huge unknown into three or four small ones you can picture.

Round boldly

Use 100,000 seconds a day or 30 million seconds a year: close enough wins here.

Count the zeros

Getting the power of ten right matters more than the first digit.

Sanity-check

Compare with something you know: a day, a city, a car trip.

Use the hint sparingly

The first step is free to see, but it keeps only 70% of the points.

Why play Estimation Sniper?

Estimating well is useful everywhere: budgets, plans, news numbers that look off. Fermi questions train the habit of breaking problems into parts and checking orders of magnitude.

Frequently asked questions