Paste a puzzle instead of typing every clue
Open Paste or copy a Sudoku grid. Enter 81 digits in row order, using 0 or a dot for an empty cell; spaces and line breaks are accepted. Import rejects malformed grids and obvious repeated clues without changing the board. Checking the grid then establishes whether there is one solution. Copy starting clues exports the original puzzle without any personal information.
Solve Sudoku one explained step at a time
After a unique solution is confirmed, choose Explain next step. Read the deduction and any candidate eliminations before applying it. Original starting clues stay black; worked numbers are blue. Reset worked steps returns to your entered puzzle, and your saved starting clues are never replaced by the walkthrough. Some difficult grids may exceed the supported logical techniques; the tool says so rather than inventing a reason.
Sudoku answers or a new puzzle to solve?
This solver checks clues you supply; it does not choose a new puzzle for you. For ready-made Sudoku puzzles with answers, select a difficulty and include the answer sheet. To solve interactively with help one move at a time, play Sudoku with hints.
Can Sudoku have multiple solutions?
Yes. A set of clues can allow several completed grids. For example, an empty 9 × 9 grid has many possible completions, so it is not a uniquely solvable puzzle. If this solver reports multiple solutions, check for a missing or mistyped clue before treating any completed grid as the intended answer. Conflicting repeated digits or a set of clues with no valid completion need a different correction.
Enter only the starting clues
Select cells and enter the printed clues from your puzzle. Leave unknown cells empty. Check that you have copied every row accurately.
What the results mean
A unique solution means exactly one completed grid fits the clues. Multiple solutions means more than one grid fits. A conflict or no solution means the input needs review.
Checking your answers
To compare a finished paper puzzle with the answer, enter only the original clues, check the grid and choose Show solution. The completed grid shows the original clues in black and the solved cells in blue.
Need help learning instead?
Use the playing grid’s Hint control for an explanation of the next logical step, or read the beginner guide. Revealing a solution is different from explaining a technique; our Sudoku tips cover the reasoning.
A few helpful answers
Yes, if it has too few clues or the wrong ones. A proper puzzle has exactly one. The solver tells you when more than one completed grid fits, rather than picking one at random.
No. The solver runs in your browser, and the clues you enter never leave this device.
Yes. The game works in your browser. Progress is saved on this device when local storage is available.