Tools
Sudoku solver — with the reasoning, not just the answer
Paste a puzzle and get the solution plus the technique path: which patterns were needed, in what order, and how hard the puzzle actually is. Everything runs in your browser — the grid never leaves this page.
How to paste a puzzle
- Type 81 characters in reading order — 9 rows of 9.
0,.and spaces are all treated as blanks, so you can paste from any site or from a book transcription.- Digits
1–9are the givens. If your source uses letters, A–I map to 10–18 only for 16×16 grids, which this solver does not handle. - Shareable links: add
?p=with the 81 characters and the page solves it on load.
What “with the reasoning” means
Most solvers return a completed grid. That is useful once and then useless: you learn nothing and cannot verify that the answer follows from the givens. This one runs the same human-technique engine that grades every puzzle on this site, so the output tells you how it got there:
- Which techniques were needed and how many times each — so you can see whether the puzzle is singles-only or needs wings.
- The hardest step, which is what actually sets the difficulty.
- A rated tier (easy / medium / hard / expert) computed from technique weights, not from counting clues.
If a puzzle has more than one solution, the solver says so instead of silently picking one: a multi-solution grid is not a valid sudoku, and no amount of logic can finish it.
Honest limits
- It solves standard 9×9 sudoku. Killer, jigsaw and 16×16 are not supported here.
- When a puzzle needs forcing chains, the technique list stops at the last single-step move and says so — the solver does not pretend a chain is a “technique”.
- Everything is client-side; there is no request, no queue and no rate limit.
Related
How difficulty is measured · The eight techniques · Printable sheets · Play a puzzle