Sudoku solver
Solve 4 × 4, 6 × 6, 9 × 9 and 16 × 16 Sudoku puzzles. Check conflicts, uniqueness and optional diagonal Sudoku constraints.
Free online · No account needed · Runs in your browser
Results
Enter your puzzle or load an example, then choose Solve puzzle.
Play Sudoku in MindGlyph
This solver works with puzzles from anywhere. For more practice, get MindGlyph’s nine word and logic games on Android and iOS. Play as a guest—no account needed.
How to use the sudoku solver
Choose the board size, enter clues or paste the board, and use 0 or . for blanks. Enable diagonal Sudoku when both main diagonals must also contain every symbol. Your original clues stay unchanged.
Try an example
Load this classic nine-row example and solve it. The solution preserves every given digit and uses 1–9 exactly once in each row, column and box.
Choose “Load example” above to try these inputs, then select “Solve puzzle” to see the results.
What the results mean
Supports standard and diagonal 4 × 4, 6 × 6, 9 × 9 and 16 × 16 boards. Six-by-six uses 2 × 3 boxes; sixteen-by-sixteen uses 1–9 and A–G. Cage, irregular and arithmetic variants are not supported. Search limits never imply uniqueness.
Keep your original puzzle nearby and compare the results with its rules. When several candidates fit, use the information you already know to narrow the next search.
Read the Sudoku strategy guide or explore the game in MindGlyph.
Sudoku solver questions
How does the sudoku solver work?
Choose the board size, enter clues or paste the board, and use 0 or . for blanks. Enable diagonal Sudoku when both main diagonals must also contain every symbol. Your original clues stay unchanged.
Can you show me an example?
Load this classic nine-row example and solve it. The solution preserves every given digit and uses 1–9 exactly once in each row, column and box.
What are this solver’s limits?
Supports standard and diagonal 4 × 4, 6 × 6, 9 × 9 and 16 × 16 boards. Six-by-six uses 2 × 3 boxes; sixteen-by-sixteen uses 1–9 and A–G. Cage, irregular and arithmetic variants are not supported. Search limits never imply uniqueness.
Is it free, and is my puzzle sent to a server?
It is free and requires no account. The search runs in your browser. The tool downloads an English dictionary or compound relationships when needed; your puzzle entries are not uploaded or saved to an account. You can cancel a search or clear your inputs at any time.