Play sudoku online for free with a brand-new puzzle every time you start a game. Fill the 9×9 grid so that every row, column and 3×3 box contains the numbers 1 to 9 exactly once. Choose Easy, Medium or Hard, use notes to pencil in candidates, and race against the timer to set a new best time. Each puzzle has exactly one solution, so you can always solve it with logic. Your game is saved as you play, so you can close the page and finish later.
How to play
- Fill each empty cell with a number from 1 to 9.
- Every row, every column and every 3×3 box must contain each number exactly once.
- Select a cell, then tap a number or use your keyboard.
- Use Notes to pencil in possible numbers.
Controls
- Click or tap a cell, then tap a number on the number pad. The pad shows how many of each digit are left.
- On a keyboard, type 1–9, move between cells with the arrow keys and clear a cell with Backspace.
- Turn on Notes to pencil in small candidate numbers. Use Erase to clear a cell and Undo to take back a step.
Tips and strategy
- Start with the rows, columns and boxes that are almost full. They are the easiest to complete.
- Scan each number from 1 to 9 across the grid and look for the only place it can go in a box.
- Use notes on harder puzzles. When a cell has only one candidate left, you can fill it in.
- If two cells in a row, column or box can only hold the same two numbers, those numbers can be removed from the other cells there.
- Never guess. Every puzzle can be solved with logic alone.
Game modes and difficulty
Pick Easy, Medium or Hard. The harder the level, the fewer numbers you get at the start. Or press Daily puzzle: everyone gets the same Medium puzzle that day, and solving it on days in a row builds your streak. Wrong numbers turn red and count as mistakes, and your best time is saved for each level.
History and background
Sudoku builds on the old mathematical idea of Latin squares, grids in which each symbol appears once in every row and column. The modern puzzle, with its extra rule for 3×3 boxes, appeared in American puzzle magazines in the late 1970s under the name Number Place.
It then became very popular in Japan, where it got the name sudoku, roughly meaning “single number”. In the mid-2000s it spread around the world through newspapers and became one of the best-known logic puzzles. No math is needed, only careful reasoning.
Frequently asked questions
Does every sudoku have one solution?
Yes. Every puzzle generated here has exactly one solution, so it can be solved by logic without guessing.
Are the puzzles always different?
Yes. A new puzzle is made every time you start a game. The Daily puzzle is the exception: it stays the same all day, and a new one comes the next day.
What does a red number mean?
A number shown in red is wrong for that cell. It also adds one to your mistake counter.
Can I play sudoku on my phone?
Yes. Tap a cell and then a number on the number pad. It works on phones, tablets and computers.