Sudoku Game

How to Play Sudoku

Fill the empty cells with the digits 1 through 9. Each row must contain every digit once, each column must contain every digit once, and each outlined 3 × 3 box must contain every digit once. Given numbers are fixed clues. Every Sudoku generated here is checked to have exactly one solution.

Select a cell and use the number buttons below the board, or type a digit on your keyboard. The selected row, column and matching values are highlighted to help you scan. Repeated digits are marked with an underline and described in the status message, so colour is not the only signal.

Turn Notes on to record possible digits in an empty cell. Press a digit again to remove that note. Turn Notes off to enter the final value. Erase removes a value or its notes. Check puzzle marks incorrect entries, and Hint fills a selected editable cell or another unfinished cell.

Find a Missing Digit

Suppose a row already contains 1, 2, 3, 4, 5, 6, 8 and 9. Its final cell must be 7. Before entering a candidate in a less complete row, also inspect that cell’s column and 3 × 3 box. A number that is missing from the row may already be present in one of those other groups.

If a cell could contain 2, 5 or 7, add those three pencil notes. As you solve neighbouring cells, review the notes and remove candidates that no longer fit. Notes are your own working marks; the game does not automatically delete every note when nearby values change.

Easy begins with more given numbers, Normal removes more clues, and Hard aims for fewer starting clues while preserving one solution. These are clue-based levels rather than a formal rating of every solving technique. Take as much time as you need; there is no time limit or penalty for replacing an entry.

Play a Daily Sudoku or Resume Practice

Daily Sudoku changes at midnight UTC. Visitors using the same difficulty and date receive the same puzzle. Switch to Practice for additional grids, and press New game whenever you want a different puzzle. Restart reproduces the current daily grid.

Entries, notes and playing time are saved automatically in this browser. Returning to the same mode and difficulty resumes that game. The clock starts with your first interaction, pauses in a hidden tab and resumes when you return. Clearing browser data removes these local records; progress is not transferred to another device.

Completed daily puzzles build a streak. Assisted completions are recorded, while your fastest-time record uses games finished without hints. Check puzzle is available throughout the game. Your completed grid stays visible so you can review the result.

Frequently Asked Questions

How do keyboard controls work?

Arrow keys move between cells. Digits 1–9 enter a value, N toggles notes, and Backspace, Delete or 0 erases. Enter checks the puzzle. Tab reaches the other controls.

Can a puzzle have multiple solutions?

No. The generator counts solutions as it removes clues and keeps a removal only when exactly one solution remains.

What happens when a new daily puzzle arrives?

A newly opened Daily game uses the current UTC date. A page left open overnight displays a notice; switch to Practice and back to Daily to open the new grid.