Type a puzzle in, paste it, or photograph it — then get the solution along with the reasoning that produces it.
You can fill the grid by hand, clicking cells and choosing digits from the keypad or typing 1–9 directly. Hold Ctrl to select several cells at once, and use Delete or Backspace to clear. For a puzzle you already have as text, paste an 81-character string and the grid fills itself.
The third route is a photograph. The importer runs optical character recognition in your browser, reads the givens off a picture of a printed grid, and drops them into the solver. Recognition is not flawless on a low-contrast newspaper scan, so check the imported digits before solving — a single misread given produces a puzzle with no valid solution.
The solver does not just hand you a filled grid. It first checks the grid is legal, then reports whether the solution is unique — and when a puzzle admits several, it finds them and lets you step between the first three rather than silently picking one.
The site's own 146,764 Classic puzzles are graded on a five-level scale by the hardest technique each one actually requires: Easy needs only Naked Singles, Medium adds Hidden Singles and Locked Candidates, Hard brings Pairs, Triples and Unique Rectangles, Extreme reaches X-Wings, Skyscrapers and Coloring, and Diabolical demands XY-Chains, Finned Fish and ALS.
Solving a puzzle for you is the least interesting thing you can do with it. Hand any puzzle to the play board and the Next Step button walks it one logical step at a time, naming the technique behind each one — and every technique it names has a full guide in the Learning Hub, so when a Skyscraper resolves the cell you were stuck on you can go and learn the pattern rather than just accept the digit.
Any valid puzzle you enter can also be handed straight to the play board, so you can attempt it properly with the timer running instead of watching it get solved.
The solver deliberately refuses any puzzle that is currently live in a competitive event — an active tournament, an in-progress duel, the Classic Daily Challenge or any Daily Triple puzzle. That block is global: it applies across every device and browser, not just yours.
Matching is done on the givens, so pasting a partially filled board does not get around it. The check also fails closed: if the lookup itself errors, the solver refuses rather than risking an answer to a live competitive grid. Once the event ends, the puzzle unlocks normally.
Yes, completely, with no account required. There is no limit on how many puzzles you can solve.
It solves any legal 9×9 grid. If the solution is unique it says so; if there are several it still solves them, reports how many it found, and lets you browse the first three; if there are none, it tells you instead of guessing.
Yes. The image importer runs OCR in your browser to read the givens. Verify the recognised digits before solving, especially on low-contrast scans.
Not on the Solver page itself — there it returns the filled grid and the solution count. For the reasoning, hit “Play This Puzzle” to send the grid to the play board, where the Next Step button walks the solve one logical step at a time and names the technique behind each one. Every technique it names has a full guide in the Learning Hub.
Puzzles that are live in a tournament, a duel, the Classic Daily Challenge or the Daily Triple are blocked globally while the event runs. This keeps competitive play fair, and it unlocks once the event ends.