About the game

Sudoku Online is a free browser puzzle where you fill a 9×9 grid with digits 1 to 9 so each digit appears exactly once in every row, column and 3×3 box. Some cells start pre-filled as clues. Pick Easy, Medium, Hard or Expert and work from the cells with the most filled neighbors, since fewer options make the right digit easier to spot.

Every puzzle has exactly one solution, reachable through pure logic. If you get stuck, a step was missed somewhere and it can always be traced back. Notes mode lets you pencil in candidates and cross them off as the grid fills. Extra modes add diagonal rules, highlighted regions, target sums or ratio and difference markers.

How to play

Click a cell, then enter a digit from 1 to 9.
Each digit must appear once per row, column and 3×3 box.
Use notes mode to write candidates in a cell and remove them as you go.
Start with cells that have the most filled neighbors to narrow the choices.

Sudoku Online

About the game

How to play

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