About

The Math Behind Everything is a series of short videos that work out the real odds behind everyday questions, and this site is where you can play them.

What it is

Each video takes one question, like whether a room of strangers shares a birthday, how close you'd come to a plane if you were dropped from 50,000 feet, or whether you've been in a Fortnite lobby with a celebrity, and works out the answer step by step from real data.

Most videos come with a game or tool here, so you can try the odds yourself instead of taking my word for it. Play first, then read how the math works. The articles go through each one in full, with the numbers, the assumptions and the sources.

How the numbers are made

Every number starts from a published source: a research paper, a government dataset, official game rules or prices pulled from the store. Where a question needs an assumption, the article says what it is and why. The games use the same numbers as the videos, so what you see on screen is what you can play.

If you find a mistake, tell me and I'll correct it.

Improbable

Improbable is a game of pure chance with the odds shown for every result: a daily game, levels from 1 in 2 to 1 in a million, and challenges. It's free on this site, and the app is coming to iPhone.

Follow along

New videos go up on YouTube, Instagram and TikTok. For sponsored videos or a custom game, see Work with me.