Sudoku – Free Online Puzzle (Easy to Hard)
Play free Sudoku online with Easy, Medium and Hard puzzles that always have one unique solution — with pencil notes, hints, undo and a timer.
How to play
- 1
Choose Easy, Medium or Hard. A new puzzle with exactly one solution is made for you.
- 2
Tap an empty cell, then tap a number on the number pad (or type 1–9 on the keyboard).
- 3
Every row, every column and every 3×3 box must contain the numbers 1 to 9 exactly once.
- 4
Turn on Notes to write small pencil marks. Use Undo, Erase or Hint when you are stuck.
- 5
Fill the whole grid correctly to win. Your best time for each level is saved.
Tips
- Start with the number that already appears most often on the grid — it has the fewest places left.
- Look for “hidden singles”: a number that can go in only one cell of a row, column or box.
- Use Notes on Medium and Hard. Write all candidates in a box, then cross them out as you place numbers.
- Tap a filled number to highlight all its copies — empty spots that are not covered stand out quickly.
About this game
Sudoku is a number placement puzzle played on a 9×9 grid divided into nine 3×3 boxes. Some numbers are given at the start; your job is to fill every empty cell so that each row, each column and each box contains the digits 1 to 9 exactly once. No arithmetic is needed — only logic.
This free version creates a fresh puzzle every time, in three levels, and checks that each one has a single unique solution. You can write pencil notes, highlight matching numbers, undo moves, ask for a hint and see your mistakes. It works with touch and keyboard, and your best time for each level is saved only on your device.
Free to play · no sign-up · no ads · your best scores are saved only on this device.
Questions
Does every puzzle have only one solution?
Yes. Each puzzle is generated in your browser and checked by a solver, so it has exactly one correct answer. You never need to guess.
What is the difference between Easy, Medium and Hard?
Easy puzzles give about 38 numbers and can be solved by simple elimination. Medium gives about 31 numbers. Hard gives fewer numbers and needs advanced ideas such as candidate notes and pairs.
Is Sudoku good for students and older people?
Sudoku is a calm logic exercise that trains concentration and patience. Many students use a short game as a study break, and many grandparents enjoy one with their morning tea. It is fun practice, not a medical treatment.
Does it work on a basic Android phone?
Yes. It runs in any modern browser, uses very little data after the page loads, and the large number pad is made for touch screens.
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