Play Free Sudoku Online

Play Sudoku in your browser—no download, no sign-up. Choose classic 9×9 or Killer Sudoku with cage sums, track your time and score, and improve with hints and multiple difficulties.

What Is Sudoku?

Sudoku is a number-placement puzzle on a 9×9 grid divided into nine 3×3 boxes. The goal:

Fill the grid so that every row contains the digits 1–9 exactly once.
Every column contains 1–9 exactly once.
Every 3×3 box contains 1–9 exactly once.

Some cells start with given numbers (clues); you fill the rest using logic only—no guessing required.

How to Play

Select a cell by clicking or tapping it.
Enter a number using the on-screen keypad or keyboard (1–9).
Notes mode lets you pencil in candidates in empty cells; turn it on with the Notes toggle.
Clear removes the number or notes from the selected cell; Hint reveals the correct digit for that cell (with a score penalty).
Complete the grid with no duplicates in any row, column, or box to win.

Killer Sudoku Mode

In Killer Sudoku, the grid is divided into cages (outlined regions). Each cage has a small number in one corner—the cage sum.

The digits inside a cage must add up to that sum.
Within a cage, digits still cannot repeat.
Standard Sudoku rules (unique 1–9 per row, column, and 3×3 box) still apply.

Use the cage sums and logic to narrow down possibilities and solve the puzzle.

Difficulty Levels

Super easy – More clues; good for learning.
Easy – Fewer clues; still forgiving.
Medium – Balanced challenge.
Hard – Fewer clues; requires stronger logic.

Scoring and Tips

Timer – Finish faster for a higher time bonus.
Mistakes – Wrong entries cost points; avoid them when you can.
Hints – Use sparingly; each hint reduces your score.
Killer mode – Grants a score multiplier when enabled.
Perfect run – Zero mistakes and zero hints for an extra bonus.

Play often to beat your best score per difficulty and improve your strategy.

Why Play Sudoku?

Sudoku is a popular logic puzzle that helps with concentration, pattern recognition, and number sense. It’s suitable for all ages and can be played in short sessions. This free online version works on desktop and mobile, with optional Killer mode and scoring for a bit of extra challenge.