Classic Logic Puzzle

Sudoku

Fill every row, column, and 3x3 box with the digits 1–9. Choose your difficulty, think logically, and solve the grid.

Click a cell, then type 1–9 or use the number pad above. Arrow keys move the selection.

How to play

Sudoku — Classic Number Puzzle in Your Browser

Sudoku is a logic-based number-placement puzzle played on a 9x9 grid divided into nine 3x3 boxes. The objective is straightforward: fill every row, every column, and every 3x3 box with the digits 1 through 9, using each digit exactly once in each unit. No arithmetic required — pure deductive reasoning. This version runs entirely in your browser, generates a fresh unique puzzle each time you click New Game, and never needs an account or download.

Choose Easy (around 40 given digits) for a relaxed solve, Medium (around 32) for a satisfying challenge, or Hard (around 26) when you want to push your logical thinking to its limits. Every puzzle is machine-generated with a guaranteed unique solution. Use Check to highlight any cells that conflict with the correct answer, or reveal the full solution with Solve when you are ready to move on.

100% freeNo downloadPlay in your browserThree difficulties
How to play
  1. 1Select a difficulty — Easy, Medium, or Hard — and click New Game to generate a fresh puzzle.
  2. 2Click any empty white cell on the grid to select it. The selected cell turns blue and its row, column, and box are highlighted.
  3. 3Type a digit (1–9) on your keyboard, or tap a number on the on-screen number pad to place it in the selected cell. Press Backspace, Delete, or the ✕ button to erase a digit.
  4. 4Continue filling the grid until every cell contains a digit. The puzzle auto-detects when the board is correctly completed and shows a congratulations message.
  5. 5Stuck? Click Check to highlight any incorrect cells in red without revealing the whole solution, or click Solve to see the complete answer.
Game features
  • Three difficulty levels — Easy (~40 givens), Medium (~32 givens), Hard (~26 givens) — for players of every skill level.
  • Unique-solution puzzles: every generated board is verified to have exactly one valid solution.
  • Smart highlighting: selecting a cell illuminates its entire row, column, and 3x3 box for easier scanning.
  • Check button marks conflicting cells in red so you can self-correct without spoiling the solution.
  • Solve button reveals the full correct answer whenever you want to move on or learn from the puzzle.
  • Keyboard-first input — type digits and navigate with arrow keys for a fast desktop experience.
  • On-screen number pad for comfortable play on phones and tablets.

Frequently asked questions

Is this Sudoku game free?
Yes, completely free. There are no charges, subscriptions, or in-app purchases. Open the page and play immediately.
Do I need to create an account or download an app?
No account and no download required. The game runs entirely inside your browser — just visit the page and start playing.
What is the difference between Easy, Medium, and Hard?
Difficulty is controlled by how many digits are pre-filled. Easy leaves around 40 given digits, making deductions straightforward. Medium provides roughly 32, requiring more systematic logic. Hard gives only about 26, often demanding advanced techniques like candidate elimination across multiple units.
What is a good strategy for harder puzzles?
Start by scanning each row, column, and box to find any unit that is missing only one or two digits — those cells can often be filled immediately. Next, for each empty cell list all digits that do not already appear in its row, column, and box. If only one candidate remains, place it. Look for 'naked pairs': two cells in the same unit that share exactly the same two candidates, which lets you eliminate those digits from all other cells in that unit. Working systematically rather than guessing will solve the vast majority of hard puzzles.

Related Articles & Guides

BlogSudoku for Beginners: History, Brain Benefits and First TechniquesHow a Quiet Japanese Puzzle Conquered the World Open almost any newspaper, puzzle app, or in flight magazine and you will find a 9×9 grid waiting to be filled. ArticleHow to Solve Sudoku: Rules, Techniques & StrategyThe rules of Sudoku and a step-by-step progression of solving techniques — scanning, naked and hidden singles, pairs, and box-line reduction.Blog2048: History, Addiction, Math & Tips to WinThere is a certain kind of puzzle that feels too simple to be interesting and too interesting to put down. 2048 is that puzzle. A 4x4 grid. Numbers that double