Sudoku – Play Fresh Puzzles Generated in Your Browser
Pick a difficulty and get a brand-new sudoku with exactly one solution. Use pencil notes, hints and a mistake check, and play with the keyboard on a computer or the on-screen pad on a phone. Looking for another game? Try the Bingo Number Caller.
🔒 Runs in your browser · Your data is never sent to a server
Keyboard: arrow keys move, 1–9 enter a number, 0, Backspace or Delete erase, N toggles notes.
How to use
- Choose a difficulty (Easy, Medium or Hard) and press “New puzzle”.
- Select an empty cell by clicking or tapping it, then type a number or use the on-screen number pad.
- Turn on “Notes” to pencil in small candidate numbers. If you get stuck, use “Hint” or “Check mistakes”.
- Fill every cell correctly to win. Press “Restart” to try the same puzzle again.
Notes
- Each puzzle is generated at random in your browser, and a solver confirms it has exactly one solution. Getting the same puzzle twice in a row is very unlikely.
- Difficulty is set by the number of given cells (about 40 for Easy, 32 for Medium, 26 for Hard). Fewer givens usually means a harder puzzle, but the techniques required are not guaranteed.
- Repeated numbers turn red as you type. “Check mistakes” compares your entries with the unique solution, and “Hint” fills one cell with the correct number.
- Reloading the page discards the current game and starts a new puzzle.
- Printing, entering your own puzzle and auto-solving are not supported.
Glossary
Sudoku
A puzzle where you place 1 to 9 in a 9×9 grid so that every row, every column and every bold-outlined 3×3 box contains each digit exactly once.
Unique solution
A puzzle with exactly one valid answer, so it can be solved by logic without guessing. This tool counts solutions with a solver and only serves puzzles with one.
Pencil notes (candidates)
Small numbers jotted in a cell to track which digits could still go there. Filling cells that are down to a single candidate is the basic way to progress.
FAQ
Does every puzzle have exactly one solution?
Yes. While a puzzle is built, the solver counts solutions after every cell is removed, and any removal that would allow two or more solutions is undone. Each puzzle can therefore be solved by logic alone.
How is the difficulty decided?
By the number of given cells: about 40 for Easy, 32 for Medium and 26 for Hard. Fewer givens means fewer clues and usually a harder puzzle, but puzzles are not graded by the solving techniques they require.
How do pencil notes work?
Keep “Notes” on, select an empty cell and press a number to pencil it in; press the same number again to remove it. When you place a number normally, matching notes are cleared automatically from the same row, column and box.
What is the difference between Hint and Check mistakes?
Hint fills one empty cell with the correct number (the selected cell if you picked one). Check mistakes compares what you have entered with the unique solution and highlights wrong cells in red without changing anything.
What happens if I close the page mid-game?
Progress is not saved, so reloading gives you a new puzzle. Nothing about your game is sent to any server.
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