Does every puzzle have only one solution?

Yes. Each puzzle is generated from a full valid grid and cells are removed only while the solution stays unique, so you never need to guess.

What is the difference between the levels?

Easy starts with about 38 given numbers, Medium about 32 and Hard about 27. Fewer clues usually means harder logic.

What does the Hint button do?

It fills in one correct cell, the selected one if it is empty or wrong, otherwise a random one. Hints are counted and shown above the board.

Is my game saved if I refresh the page?

Yes. The current puzzle, your numbers, notes and timer are saved in your browser on this device, so you can continue later.

How are best times recorded?

The fastest solve for each level is saved on this device. Only games finished without hints count towards a best time.

How do pencil notes work?

Turn on Notes and tap numbers to toggle small candidates in a cell. When you place a number, it is removed from the notes of its row, column and box.

Does it work on a phone?

Yes. The board scales to your screen, the number pad has big tap targets and puzzles generate in a fraction of a second. Fullscreen gives you a larger board.

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Sudoku

Fill the grid so every row, column and 3x3 box holds the digits 1 to 9. Every puzzle has exactly one solution.

Quick Answer

Sudoku lets you: Fill the grid so every row, column and 3x3 box holds the digits 1 to 9. Every puzzle has exactly one solution. To start, choose Easy, Medium or Hard. A new puzzle is generated instantly in your browser.

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How to use this tool

1
Pick a level
Choose Easy, Medium or Hard. A new puzzle is generated instantly in your browser.
2
Select a cell and enter a number
Tap an empty cell, then a number from the pad. On a keyboard use the digits, the arrow keys and Backspace to erase.
3
Use notes
Switch on Notes to pencil in small candidate numbers. Placing a number clears it from the notes of its row, column and box.
4
Check, hint and undo
Matching numbers and the selected row, column and box are highlighted, and duplicates turn red. Use Undo to step back or Hint to reveal one correct cell.

Frequently Asked Questions

Minesweeper

Clear the board without hitting a mine. Use the numbers to work out where the mines are hiding.

Sliding Puzzle

Slide the numbered tiles into order, 1 up to the last number, with the gap in the bottom-right corner.

Sudoku

How to use this tool

Pick a level

Select a cell and enter a number

Use notes

Check, hint and undo

Frequently Asked Questions

Does every puzzle have only one solution?

What is the difference between the levels?

What does the Hint button do?

Is my game saved if I refresh the page?

How are best times recorded?

How do pencil notes work?

Does it work on a phone?

Related Tools

Minesweeper

Sliding Puzzle

Sudoku

How to use this tool

Pick a level

Select a cell and enter a number

Use notes

Check, hint and undo

Frequently Asked Questions

Does every puzzle have only one solution?

What is the difference between the levels?

What does the Hint button do?

Is my game saved if I refresh the page?

How are best times recorded?

How do pencil notes work?

Does it work on a phone?

Related Tools

Minesweeper

Sliding Puzzle