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Countdown Solver

A cross-platform desktop app that solves the two puzzle games from the UK TV show Countdown — handy at home, or for double-checking a contestant's working:

  • Numbers — pick six numbers and a target between 100 and 999, and the solver finds an arithmetic expression (+ - x /, each number used at most once, no fractions or negative numbers along the way) that hits the target exactly, or gets as close as possible.
  • Letters — pick nine letters, and the solver finds every valid word hiding in them, longest first.

There's a third game on the show, the Conundrum (unscramble nine letters into one word), which the app can generate and solve too.

Numbers page

Try it

Grab a build from the project's releases, or build it yourself — see Getting started. New to the app? How to play walks through each round and what the results mean.

A tour of the app

Letters page

Conundrum page

Settings page

Also on Android

The same app runs natively on Android too — tablet and phone, portrait and landscape — with a bottom tab bar in place of the desktop sidebar on those smaller/narrower screens. (iOS targets the same breadth but is unverified on real hardware — see Building & packaging.)

Numbers page on an Android tablet, landscape orientation

Numbers page on an Android tablet, portrait orientation

Numbers page on an Android phone, landscape orientation

Numbers page on an Android phone, portrait orientation

Under the hood

All the game logic lives in a small, dependency-free C++23 library, countdown::solver, with no GUI or platform code in sight — it's unit tested on its own and could be dropped into a different frontend entirely. A thin Qt 6 Quick (QML) app sits on top for the GUI you see above. See Architecture for the tour.

License

CountdownSolver is free and open source under the GPL-3.0-or-later license. Contributions are welcome — see Contributing.