× Puzzle

Sudoku

Fill the 9x9 grid so that every row, every column and every 3x3 box holds the digits 1 to 9 exactly once. Every puzzle has one solution and is made fresh for you.

👆 Tap a cell, then tap a number · Notes for pencil marks ← All games

Sudoku

Added 8 Nov 2026

Play sudoku free in your browser: classic 9x9 number puzzles from Easy to Hard, each one made fresh with exactly one solution, with pencil notes, hints and undo.

How to play

The board is a 9x9 grid split into nine 3x3 boxes. Some cells already hold a digit; these clues are printed in bold and cannot change. Your job is to fill every empty cell so that each row, each column and each 3x3 box contains the digits 1 to 9 exactly once. No digit may repeat inside a row, a column or a box.

Tap an empty cell to select it, then tap a digit on the number pad under the board. The row, column and box of the selected cell light up, and so does every cell holding the same digit, which makes it easy to see where a number can still go. A correct digit is written in blue. A wrong digit flashes red and is not written in; on Medium and Hard that counts as a mistake, and the third mistake ends the game.

Turn on Notes to write small pencil marks for the candidates you are considering. Tap a digit again to remove its note, or Erase to clear the cell's notes. When you place a digit, it disappears from the notes of every cell it rules out. Hint fills in a cell you could prove right now, Undo takes back your last step, and the small number under each pad key shows how many of that digit are still missing. Placing correct digits quickly in a row builds a streak that adds bonus points.

Strategy tips

• Start with the digit that already appears most often on the board. Tap it on the board to see every row, column and box it still needs.
• Look for naked singles: an empty cell where eight of the nine digits are already used in its row, column and box can only hold the last one.
• Look for hidden singles: inside one box, a digit that can only go in one cell must go there, even when that cell has other candidates.
• On Hard, write notes. When two cells in a unit share exactly the same two candidates, those two digits can be removed from every other cell in that unit.
• If a digit's candidates inside a box all sit in one row, that digit cannot be anywhere else in that row outside the box.
• Never guess on Medium or Hard. Every puzzle can be solved by logic alone, and a guess risks one of your three mistakes.

Modes

Easy gives 38 to 42 clues, can always be solved by finding singles, and has no mistake limit, so it is a good way to learn. Medium gives 30 to 34 clues and allows three mistakes. Hard gives 25 to 28 clues, always needs more than singles, and also allows three mistakes. Each mode keeps its own games played, wins, win streak, best time and medals: bronze for a solve, silver and gold for fast solves without the Hint button.

FAQ

Does every puzzle have only one solution?

Yes. Each puzzle is made in your browser from a full grid, and a clue is only taken away while a solver still finds exactly one way to finish it. You never need to guess.

What is the difference between Easy, Medium and Hard?

Easy gives 38 to 42 clues and can always be solved by finding single candidates. Medium gives 30 to 34 clues. Hard gives 25 to 28 clues and always needs more than singles, such as pairs or pointing digits in a box.

What happens when I enter a wrong number?

The number flashes red and is not written in. On Medium and Hard it counts as a mistake, and the third mistake ends the game. Easy has no mistake limit.

How do pencil notes work?

Tap Notes, then tap digits to write small candidates in the selected cell. Tap a digit again to remove it. When you place a number, that note disappears from every cell in the same row, column and box.

Is my game saved if I close the page?

Yes. The puzzle, your numbers, your notes and the timer are kept in your browser, and the start screen offers to continue. Your best times and win streak are kept for each mode.

Can I play sudoku on my phone?

Yes. The board and number pad are sized for a phone screen: tap a cell, then tap a number. It runs in any browser with no download and no account, and a keyboard works too on a computer.

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