Play Sudoku with friends

Yay you did it! You completed the Sudoku puzzle in

Play this Sudoku puzzle with your friends, helping you finish even more quickly! Just share the link however you like and you'll all complete it together.

Multiplayer Mode

Choose how you want to play with your friends.
Other players have joined the game, so it is not possible to change the multiplayer mode

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Playing Countdoku

Welcome to Countdoku, the multiplayer Sudoku game.

Three things make Countdoku different to other Sudoku games

  1. Games vary in size and complexity, from simple 4x4 games for small kids, to huge 25x25 games for groups to solve together. Change the game size any time by clicking the Game Size Icon button.
  2. Both single player and multi player games are supported. To play with one or more friends (there's no limit) just click the Players Icon button and share the link with as many people as you like
  3. Colours are used in place of numbers for the easier games. If you prefer a more traditional Sudoku experience, change your preference here.

About Countdoku

Countdoku is a fun little game built by Shane O'Sullivan. It's free and always will be. If you're interested to see more things by me, check out

How to play Sudoku

The goal of Sudoku is to fill the entire grid with numbers so that each row, column and square box contains all the digits possible. For example, in a 9x9 grid, you must fill all the numbers 1 to 9, in a 16 x 16 grid, you fill the numbers 1 to 16.

Each number can only appear once per row, once per column and once per box. Good luck!