Sudoku Solver — Solve Any Puzzle Instantly
Stuck on a newspaper Sudoku? The AnyWordSolver Sudoku Solver takes any valid 9×9 puzzle and computes its unique solution in milliseconds using backtracking search with constraint propagation. Enter the givens, hit Solve, and get the complete grid — plus a built-in generator for fresh practice puzzles at every difficulty. Free, instant, no login.
How to Use the Sudoku Solver
- Enter the givens: type the known numbers from your newspaper, book, or app puzzle into the blank 9×9 grid. Leave unknown cells empty.
- Hit Solve: the engine validates the input, then fills every remaining cell with the unique solution — or tells you if the puzzle has no solution or multiple solutions.
- Study the answer: compare the solution against your stuck position. The cells where you diverged reveal exactly which deduction you missed.
- Generate practice: use the built-in generator to create fresh puzzles at Easy, Medium, Hard, or Expert — or play them directly in our Sudoku game.
Sudoku Rules Refresher
- Rows & columns: every row and every column must contain the digits 1–9 exactly once.
- 3×3 boxes: the grid splits into nine 3×3 sub-grids, each of which must also contain 1–9 exactly once.
- No math required: despite the digits, Sudoku is pure logic and elimination — no arithmetic.
- Unique solution: a proper Sudoku has exactly one solution. Our solver verifies uniqueness, so ambiguous puzzles get flagged, not faked.
Learn From the Solver — 5 Techniques It Demonstrates
- Naked singles: a cell whose row, column, and box already contain 8 different digits must be the 9th. Spot these first — they cascade.
- Hidden singles: within a row, column, or box, a digit with only one legal cell must go there even if that cell has other candidates.
- Naked pairs: two cells in one unit sharing exactly the same two candidates (say 3 and 7) claim those digits — eliminate 3 and 7 from every other cell in that unit.
- Pointing pairs: when a digit's candidates inside a box all sit in one row or column, eliminate that digit from the rest of that row or column outside the box.
- X-Wing (advanced): a digit appearing in exactly two cells in two rows, aligned in the same two columns, eliminates that digit from all other cells in those columns.
Solver vs Practice — When to Use Each
Use the solver to unstick yourself: enter the position, solve, find where you diverged, learn the missed technique, then replay similar puzzles in the Sudoku game at increasing difficulty. Solvers that only hand you answers build dependence; solvers paired with deliberate practice build skill. That is exactly how this page is designed to be used.
Common Solver Mistakes
- Entering givens in wrong cells. One transposed digit produces a "no solution" error or a wrong answer. Double-check each given against the source puzzle before solving.
- Solving instead of learning. If you copy answers without studying where you diverged, the next identical pattern will stump you again. Always identify the missed technique.
- Trusting ambiguous puzzles. Some app puzzles have multiple solutions due to generation bugs. If our solver flags non-uniqueness, the puzzle itself is broken — find a better source.
Import Tips — 81-Digit Strings
Many sites share puzzles as 81-character strings (row by row, 0 or . for blanks, e.g. 530070000600195...). Paste the full string into the import box and hit Load — the grid fills instantly. This is the fastest way to transfer newspaper, book, and app puzzles into the solver.