Sudoku
Fill every row, column, and 3x3 box with the numbers 1 to 9. Every puzzle has exactly one solution, and your best time is saved right here in your browser.
Select a cell, then type a number from 1 to 9 or use the number pad. Arrow keys move between cells, and Backspace or Erase clears a cell.
Solved!
How to play Sudoku
Sudoku is a logic puzzle on a 9x9 grid split into nine 3x3 boxes. Some cells start with a number. Your goal is to fill every empty cell so that each row, each column, and each 3x3 box contains the numbers 1 to 9 exactly once. Numbers in dark bold type are part of the puzzle and cannot be changed. The numbers you add appear in blue, and you can change or clear them at any time. Choose Easy, Medium, Hard, or Expert to change how many numbers are filled in when the puzzle starts: fewer starting numbers means a harder puzzle.
Frequently asked questions
Yes. Each puzzle is generated in your browser and checked by a solver before you see it. A clue is only removed if the grid still has exactly one solution, so you never need to guess.
No. Sudoku runs entirely in your browser. Your best time for each difficulty and your sound setting are stored only in your browser's local storage, and nothing is sent to a server.
Yes. Tab moves into the grid, the arrow keys move between cells, the number keys 1 to 9 fill the selected cell, and Backspace or Delete clears it. A visible outline shows the selected cell at every step.
If a number clashes with the same number in its row, column, or 3x3 box, every cell involved is marked with a warning icon and a wavy underline. You can keep playing and fix it whenever you like.