Free unlimited Sudoku
The classic number puzzle — fill every row, column and 3×3 box with the digits 1 to 9. Easy, medium and hard boards, a daily challenge with streaks, hints and mistake highlighting. No registration, no download.
About this Sudoku
Sudoku is the world's most popular logic puzzle. Every board here is generated fresh and is guaranteed to have a single solution reachable by pure logic — no guessing. Pick your difficulty, or take the shared Daily Challenge and build a streak.
How to play
- Each row, each column and each 3×3 box must contain the digits 1–9, once each.
- Tap a cell, then tap a number — or use your keyboard.
- Duplicate numbers are highlighted so you can spot mistakes.
Frequently asked questions
- Is it free?
- Yes — free and unlimited, supported by ads.
- Do I need an account?
- No — no sign-up and no registration needed. Your streak and best times are saved in your browser.
- Are the puzzles always solvable?
- Yes — every board has exactly one logical solution.
Difficulty levels & quick tips
Easy boards solve with scanning and "last empty cell" alone — perfect for a quick break. Medium mixes in single candidates and naked pairs. Hard rewards pencil-marking plus techniques like pointing pairs and box/line reduction. Whatever the level, a few habits speed you up:
- Scan one digit at a time across the whole grid before moving on.
- Finish near-complete rows, columns and boxes first — the last cell is free.
- Pencil in candidates for tight cells and keep them updated as you place digits.
- Trust the logic — a proper board never needs a guess.
Want the full method? Read the Sudoku strategy guide.