Sudoku

Start with one square you can explain

Fill each row, column and 3×3 box with the digits 1–9, using each digit exactly once in each group. The printed starting numbers stay fixed. There is no arithmetic: solve by finding which numbers still fit.

1. Choose Easy for your first game. Look for a row, column or box that already has plenty of numbers.
2. Select an empty square. Check its row, column and box before choosing a number from the keypad.
3. Use Notes for possibilities. Small pencil marks help you remember candidates while leaving the square unanswered.
4. Ask for a hint when stuck. Read the reason behind the next move, then look for the same pattern elsewhere.

For a worked example and a simple scanning routine, read how to play Sudoku for beginners.

A difficulty for the break you have

Easy focuses on finding squares with just one possible number. Medium adds numbers that fit in only one place within a row, column or box. Hard brings in candidate eliminations such as locked candidates and pairs. A puzzle’s challenge depends on the reasoning it needs, not just how many blanks you see.

The Daily option opens the same Medium puzzle for that UTC calendar date. The date changes at midnight UTC, which may fall at a different local time. There is no need to race anyone: pause whenever you like and hide the timer if it distracts you.

Undo and Redo let you revisit your work. Check and hints are optional assistance, recorded with the puzzle, so a completed board can distinguish helped play from a solve without assistance.

Your puzzle is saved on your device

The board, notes and progress are saved locally when browser storage is available. Saved puzzles lets you return to recent boards; the game keeps up to 24. Staying in the same browser matters: clearing site data, private browsing or changing devices can remove or separate your progress.

Share a puzzle link to give a friend the same starting board and difficulty. They choose whether to open it, and their own saved puzzles remain separate. A link carries the puzzle identity, not your answers, notes or time. Daily links keep the original date.

Play at your own pace and compare approaches afterward. Sudoku runs entirely on your device; there is no account, live room or online leaderboard.

Comfortable on a phone. Quick on a keyboard.

On mobile, tap a square and then a number. The number pad and Notes control stay close to the board, and the page supports browser zoom. Portrait is a natural fit; a tablet or desktop gives the board more room.

On desktop, click a square or move with the arrow keys, type 1–9 to enter a digit, and use Backspace or Delete to erase it. N toggles Notes. Ctrl/⌘ Z undoes a move; Ctrl/⌘ Shift Z redoes it. The on-screen controls are also available with a mouse.

Pause hides the board and stops the timer. Dialogs and a hidden browser page also suspend timed play, so returning from a break does not add the time away.