Project Euler

What Project Euler actually is

More than nine hundred numbered problems need both a mathematical insight and a short program to compute the answer. Brute force works for the first handful and then stops working entirely, at which point the problems start teaching number theory whether you intended to learn it or not.

Why it is worth your time

Each problem is tuned so that a well-chosen insight runs in under a minute while the obvious loop would still be running next year.

Common questions

Is Project Euler free?

Project Euler is free to use, but you need to create an account before you can do much with it.

How long does Project Euler take?

Clear your evening. We warned you. We file it under "Rabbit hole" — maths problems you solve by writing a bit of code.

Does Project Euler work on a phone?

Project Euler really wants a mouse and a wide window. It will load on a phone, but the experience is built for desktop.

What kind of site is Project Euler?

We list it under Mind Benders — one more round, then bed. definitely. Each problem is tuned so that a well-chosen insight runs in under a minute while the obvious loop would still be running next year.