Is this Sudoku game free?

Yes, completely free. No login, no subscription, no ads — ever.

Do I need to download anything to play?

No download needed. Play directly in your browser on any device — desktop, tablet or mobile.

What difficulty levels are available?

Four difficulty levels: Easy (great for beginners), Medium, Hard, and Expert (for advanced players).

How do I use notes in Sudoku?

Toggle the Notes button to pencil in candidate numbers. Smart Mode automatically clears notes when you place a confirmed number in the grid.

How many mistakes am I allowed?

The number of allowed mistakes depends on the difficulty. Harder difficulties allow fewer mistakes, increasing the challenge.

Can I undo a move in Sudoku?

Yes. Tap the Undo button or press Ctrl+Z on your keyboard to revert your last move at any time.

Does Sudoku work on mobile?

Yes. The game is fully optimized for mobile, tablet and desktop browsers with a responsive layout.

What is Smart Mode in Sudoku?

Smart Mode automatically removes candidate notes from related cells (same row, column and 3×3 box) whenever you place a correct number, keeping your notes up to date.

Is there a dark mode?

Yes. Toggle dark mode from the moon icon in the top navigation bar for a comfortable experience in low light.

How do I know how many of each digit are left to place?

The number pad shows a small count below each digit indicating how many times that number still needs to be placed. When a digit reaches zero, it is grayed out automatically.

Play Sudoku Online Free

Free online Sudoku puzzle game by Simply Play Labs. No login or download required. Choose from Easy, Medium, Hard or Expert difficulty and play instantly in your browser on any device.

Features

Four difficulty levels: Easy, Medium, Hard and Expert
Smart notes mode — auto-clears candidates on placement
Hint system to reveal correct digits
Unlimited undo support
Dark mode for comfortable night play
Digits remaining counter on number pad
Pause and resume at any time
Works on desktop, tablet and mobile

How to Play Sudoku

Choose a difficulty level to start a new puzzle.
Fill every row, column and 3×3 box with digits 1–9 with no repeats.
Use Notes mode to pencil in candidate numbers.
Tap Hint to reveal the correct digit for any empty cell.
Undo any mistake instantly with the Undo button or Ctrl+Z.

Please enable JavaScript to play the game.

Contact: hello@simplyplaylabs.com