Sudoku Solver
Type in any 9×9 Sudoku puzzle and solve it instantly.
Last updated
Type your puzzle's known digits, then hit Solve.
About this tool
Click a square and type a digit 1–9 (or use Tab / arrow keys to move around, Backspace to clear). Leave a square blank for the solver to fill in. Conflicting digits — the same number twice in a row, column, or 3×3 box — are highlighted in red as you type, and the puzzle won't solve until they're fixed.
The solver uses backtracking with constraint checking: it tries a valid digit in the first empty square, recurses, and backs up whenever it hits a dead end, until every square is filled consistently. If a puzzle has no valid solution, it says so instead of guessing.
Nothing typed here is sent to a server — the entire solver runs as JavaScript in your browser tab.