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Sudoku Solver

Solve any sudoku puzzle instantly.

Type a digit 1 to 9 in each cell. Provided cells show in blue. Solved cells show in gray.

About

Type in your puzzle (or paste from a string). The solver finds the answer using backtracking with constraint propagation. Also flags invalid puzzles.

How to use

  1. Click cells to enter known numbers.
  2. Click Solve.
  3. See the completed grid.

FAQ

Does it find unique solutions?+

It finds one valid solution. If the puzzle has multiple solutions, you get one of them. Real sudokus should have exactly one.

How fast is it?+

Hardest known sudokus solve in under 100ms with this approach.