For larger controls, rotate your phone or choose Expand above the game.
How to play Sudoku
Play free online Sudoku in your browser. Complete every row, column, and 3x3 box with the numbers 1 to 9—no download or signup required.
Guide checked against gameplay:
Objective, rules, and result
Fill all 81 cells with digits 1 through 9, without repetition in any row, column, or 3x3 box. This version checks entries against its generated solution immediately: a different digit costs one mistake, and the third mistake ends the puzzle. Finishing reports time and mistakes, not a points score.
How to play
- Choose a difficulty and select an empty square.
- Type 1 to 9 or use the number pad; use Notes for candidates and Hint when stuck.
- Match the generated solution to complete the grid. A wrong entry costs a mistake; the third ends the puzzle.
Example: Find the missing digit
If a row reads 5, 3, blank, 6, 7, 8, 9, 1, 2, its missing digit is 4. Check that 4 also fits the column and box, select the blank, then enter 4. This is an illustrative row; each new board is generated separately.
Common mistakes
- Notes are candidates, not answers. Turn Notes off before committing a digit; entering a digit removes that candidate from peer notes.
- A duplicate-free guess can still differ from the stored solution and count as a mistake. Puzzle generation does not guarantee a unique solution. Use Hint when stuck; Check reports wrong entries without spending a hint or adding a mistake.
Modes, restart, and saved progress
- Easy has 30 blanks and 5 hints; Medium 42 and 4; Hard 52 and 3; Expert 60 and 2. Medium is the initial difficulty.
- Hint fills the selected incorrect or empty cell, or the first remaining incorrect cell if the selection is fixed or correct. Undo restores the previous entries, notes, mistakes, and hint allowance while the round is active; it cannot reopen a finished puzzle.
- New Game or a difficulty tab creates a fresh puzzle. The result Play again button starts a fresh Medium puzzle. There is no in-board pause button; opening How to play pauses the scene. Unfinished grids are not saved across reloads or navigation.
Controls
Keyboard and mouse: Select cells with the mouse and type 1–9.
Touch: Tap a cell, then use the number pad.
Shortcuts: Arrow keys: move; N: notes; U: undo.
Strategies to try
- Scan rows, columns, and boxes for a digit that has only one legal position.
- Use notes for candidates, then remove candidates whenever a matching digit is placed nearby.
Device and accessibility notes
Keyboard players can move with the arrow keys, enter digits directly, toggle notes with N, and undo with U. Touch players can select a cell and use the on-screen number pad. The puzzle relies on numbers and position, not sound.
Use the Settings control above the game to turn sound or vibration off and to reduce interface motion. Expand mode can provide a larger play area. Records are stored only in this browser when storage is available.
On a small phone, use Expand and landscape for dense grids and canvas controls. These canvas games do not expose a complete board to screen readers; Memory Match and Minesweeper also require a pointer or touch to select cells. Opening the guide or hiding the tab pauses the scene without saving the unfinished board.