Loading...

Play Sudoku

00:00

About Sudoku

Sudoku is a logic puzzle: fill a 9×9 grid so each row, column, and 3×3 box contains digits 1–9 exactly once. It rewards patience and clear thinking—no maths beyond following the rules.

Quick rules

Some cells start filled. Complete the rest so every row, column, and box has digits 1–9 with no repeats.

A digit is wrong if:

  • It appears twice in the same row
  • It appears twice in the same column
  • It appears twice in the same 3×3 box

Tips on this site

Scan tight areas

Rows, columns, or boxes with few empty cells often give the next placement quickly.

Use notes

Turn on note mode to pencil in candidates; update them after each correct digit.

Avoid guessing

Every puzzle here is solvable by logic. If you are stuck, try a lower difficulty or read the strategy guides.

Learn more on Sudoku Online

Deeper guides live on their own pages—great for beginners and for levelling up.

Sudoku Online

Sudoku Online is a free, browser-based Sudoku experience built for anyone who wants to practise logic puzzles without installing an app. You get unlimited puzzles, six difficulty levels from Easy to Insane, optional notes and hints, and a global leaderboard so you can see how you compare to other players.

You can play as a guest—no account is required to start a game. If you sign in, you can save your scores to the leaderboard and keep track of your progress over time. We also offer premium downloadable puzzle packs (PDF) for offline play, sold through a secure checkout, for players who want printable collections.

The site is designed to be fast, accessible, and readable in light or dark mode. Whether you are learning Sudoku for the first time or chasing faster solve times, we aim to give you a clear, distraction-free place to play.

© 2026 Sudoku Online. All rights reserved.