Free online Sudoku in your browser — five difficulties from Starter to Expert, notes (pencil marks), instant check, timer, and dark mode. Progress saves on this device; no signup.
FAQ
How do I play?
Select an empty cell, then enter 1–9 with the pad or keyboard. Each row, column, and 3×3 box must contain 1–9 once. Bold digits are givens and cannot be edited.
What is Notes mode?
Notes mode pencil-marks candidate digits in empty cells. Switch to Normal mode to place final numbers.
Is progress saved?
Yes — automatically in this browser on your device (localStorage). No account or cloud sync.
Restart vs Clear entries?
Restart keeps the same puzzle, clears your entries, and resets timer and mistakes. Clear entries only removes your numbers and notes; timer and mistakes stay.
Is it free?
Yes. Free to play in the browser with no signup.