OMGLoftClassic games. Real players. How to play — Sudoku
Sudoku online — a free single-player game in your browser, no sign-up or download needed.
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Your goal
Enter digits from 1 to 9 so each appears exactly once in every row, column and 3×3 box. Every new puzzle has one solution. Starting digits cannot be changed.
Difficulty
Easy gives more digits and can be solved by filling cells with just one candidate. Medium also requires finding the only place for a digit within a row, column or box. Hard requires eliminating candidates through pairs and box-line relationships. Expert needs further reasoning or exploring possible assumptions.
Entering digits
Select a cell to highlight it in yellow. Its row and column are also highlighted. Enter a digit using the 1–9 keypad below or your computer keyboard. Selecting a cell does not open the phone keyboard. Arrow keys move between cells. “Delete”, Backspace or the Delete key clears a cell; other letters and symbols are not entered.
Notes and undo
The controls are above the board. Turn on “Notes” to mark possible digits in empty cells. Choosing a digit again removes that note. Entering a digit removes matching notes from its row, column and box. “Undo” restores digits and notes from before the last change; up to 200 recent changes are available.
Errors and hints
“Show errors” underlines digits repeated within a row, column or box. No underline does not guarantee a correct solution. “Hint” enters the correct digit in the selected cell; if no cell requiring a correction is selected, it fills another cell. Each hint adds 30 seconds to your result. Undoing a hint does not remove this penalty.
Results
You win when the entire board is correctly filled. Your time including penalties enters a separate leaderboard for the chosen difficulty; faster is better. Unfinished games are excluded. The completed board stays visible.