A LITTLE FOCUS. A FRESH START.
Play Classic Sudoku
Play free Classic Sudoku online, from beginner to expert. Fill the familiar 9×9 grid with notes, hints, night mode, and saved progress.
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OneStop Sudoku, wherever you go.
Website saves stay in this browser and don’t transfer to the app.
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The game loads here. Choose a difficulty to start or resume a puzzle.
LEARN THE TWIST
How to play Classic Sudoku
Classic uses only rows, columns, and regular 3×3 boxes. It is a useful starting point before trying variants with cages, lines, or extra regions.
The rules
Fill each row, column, and 3×3 box with 1–9, without repeats.
A useful first move
Start with nearly complete rows, columns, or boxes. Pencil in candidates when a cell has several possibilities, then remove candidates as nearby cells are solved.
If a row already contains 1, 2, 3, 4, 6, 7, 8, and 9, its last empty cell must be 5. With more empty cells, check each cell’s column and box to narrow the possibilities.
Controls, difficulty, and saved games
Choose Beginner, Easy, Medium, Hard, or Expert above. Select an empty cell, then tap a number or use your keyboard. Notes let you pencil in candidates; three hints are available. Three mistakes end the puzzle.
Every mode and difficulty keeps a separate save in this browser. You can switch puzzles and return to your place. Clearing site data removes these saves; they do not sync with another device or the iPhone app. Settings include night mode and optional automatic cell advancement.
Correct entries earn points. High scores are stored by mode and difficulty and update only when beaten; completed-puzzle count and day streak are shared.
FIFTEEN WAYS TO PLAY
Explore all Sudoku modes
A familiar grid, a different kind of logic. Every mode is free to play in your browser.