Sudoku solver with steps and explanation
Follow step-by-step Sudoku explanations and technique names instead of jumping straight to the completed grid.
Learn X-Wing strategyStep-by-step helper
Sudoku Solver
Check a puzzle from a book, newspaper, or another site. Paste 81 digits, solve the full grid, verify uniqueness, or reveal one logical next step with an explanation.
Solver searches
Use the Sudoku helper your way
Most solver searches are not only asking for the final answer. They are asking for confidence: check whether a puzzle is valid, find a contradiction, or learn the next safe move.
Sudoku next step solver
Use Next hint when you want one logical move while keeping the rest of the puzzle yours.
Paste 81 digit Sudoku solver
Enter 81 characters using digits for clues and 0 or a dot for blanks, then validate or solve.
Open 81 digit solverSudoku conflict checker
Use the grid to find duplicate numbers, invalid puzzles, row conflicts, column conflicts, or box conflicts before solving.
Sudoku validator
Validate a Sudoku puzzle copied from a book, newspaper, generator, or forum before spending time on a broken grid.
Validate 81 digit stringKakuro solver step by step
For cross sum puzzles, use the Kakuro helper to list valid no-repeat digit combinations by clue total and run length.
Open Kakuro solverStep-by-step solving
How to use the Sudoku solver without spoiling the puzzle
A good Sudoku solver should do more than fill the grid. Use it as a checker, a next-step hint tool, or a way to understand why a puzzle is stuck. That keeps the solving experience useful instead of turning it into a simple answer lookup.
- Enter the clues. Type the numbers from your puzzle into the grid, or paste an 81 character string into the text area. Use 0 or a dot for empty cells.
- Check the puzzle first. If the grid contains duplicate clues or contradictions, fix those before asking for a full solution.
- Use Next hint when you are stuck. This reveals one logical move and keeps the rest of the puzzle hidden, which is usually better for learning.
- Use Solve when you need the full answer. The full solve is best for checking a newspaper puzzle, verifying a puzzle you created, or studying the complete solving path.
81 digit Sudoku format
Most online Sudoku solvers read the grid left to right, row by row. Filled cells use digits 1 to 9, and blank cells use 0 or a dot.
530070000600195000098000060800060003400803001700020006060000280000419005000080079
When to use a Sudoku solver
Use a solver when you want to check whether a puzzle is valid, find a contradiction, or learn the next step without revealing the whole answer.
Why step-by-step matters
A final answer helps once. A Sudoku solver with steps and explanations teaches the logic so the next puzzle gets easier.
Common input format
Most Sudoku tools accept 81 characters. Use digits 1 to 9 for clues and 0 or a dot for empty cells, or open the 81 digit Sudoku solver for a paste-first page.
Sudoku hint solver vs full solver
A hint solver is best when you are stuck but still want to finish the puzzle yourself. A full solver is better for checking a puzzle, finding contradictions, or learning the complete path.
Sudoku conflict checker
A copied puzzle can fail if one clue was entered in the wrong row, a number repeats inside a box, or the starting clues lead to no possible solution. Use the checker to catch row, column, and 3 by 3 box conflicts before solving.
Sudoku validator
A validator is useful when you built a puzzle yourself, copied one from a forum, or pasted an 81 digit string from another tool. It confirms whether the starting grid is legal before you ask for hints.
How explanations improve solving
Technique labels help you notice patterns you can reuse later. After a few explained hints, you start seeing the same logic before pressing the button. For an advanced example, study the Sudoku X-Wing strategy.
Printable practice after solving
After learning a technique, print easy practice sheets from the Sudoku for kids printable or classroom worksheet pages.
Kakuro combination solver
Kakuro players often need a different kind of help: possible digit sets for a clue sum. Use the Kakuro sum combination calculator when a cross sum run is stuck.
Sudoku Solver FAQ
Can I paste an 81 digit Sudoku puzzle?
Yes. Paste 81 characters into the text box, using 1 to 9 for given numbers and 0 or a dot for empty cells. You can also use the dedicated paste 81 digit Sudoku solver.
Can the solver give only the next hint?
Yes. Use the Next hint button to reveal one safe move with a short explanation instead of solving the whole grid.
Does this Sudoku solver explain the logic?
The solver lists step-by-step moves and uses technique labels where possible, so you can understand why a number belongs in a cell.
Why does a Sudoku puzzle show as invalid?
A puzzle can be invalid if a row, column, or box already contains a duplicate number, or if the clues create a contradiction with no valid solution.
What does a Sudoku conflict checker find?
A Sudoku conflict checker looks for repeated clues in the same row, column, or 3 by 3 box before the solver tries to finish the grid.
When should I use a Sudoku validator?
Use a Sudoku validator when you copied a puzzle, typed your own clues, or pasted an 81 digit string and want to confirm the starting grid is legal.
Should I use a solver for every puzzle?
Use it when you are learning, checking a grid, or stuck for a long time. For regular play, a single next hint is usually better than revealing the full answer.