Sudoku: Play Free Online Puzzles

Rules & what counts

Sudoku is a logic puzzle on a 9 by 9 grid. Each row, each column and each 3 by 3 box must hold the digits 1 to 9 one time.

The puzzle starts with some digits in place. An easy puzzle starts with 36 to 40 digits, and every step needs only one row, one column or one box.

The server deals a new puzzle for every run and keeps the answer. Every puzzle has one solution. Your result is your time to the last correct digit.

Sudoku has six boards on TRIVI.GG: Easy, Medium, Hard and Expert, plus Killer Sudoku and Jigsaw Sudoku. Each board has its own leaderboard.

Select a mode and a difficulty on the start screen, then select Start. The clock starts when the grid shows.
Click or tap an empty cell, then a digit on the number pad. On a keyboard, type the digit.
A wrong digit turns red and counts as a mistake. The third mistake ends the run, and the run is not saved.
Select Notes to write small candidate digits in a cell. Notes do not count as mistakes.
Select Erase to clear a cell, or Undo to take back the last entry.
The run ends when every cell holds the correct digit.

Your result is the time from the moment the grid shows to the moment you enter the last correct digit.
On the leaderboard, a shorter time ranks higher.
Mistakes do not add time, but the third mistake ends the run. A run that ends with three mistakes is not saved.

The clock does not stop when you leave the page or change tabs. A run measures one continuous solve.
There are no hints. The game shows that a digit is wrong, but it never shows the correct digit.
A run under 40 seconds is not saved.

Howard Garns published the modern puzzle in 1979 under the name Number Place. The name Sudoku comes from Japan, where the puzzle became popular in the 1980s.
A classic Sudoku needs at least 17 given digits to have one solution. A computer search proved this in 2012.
There are about 6.67 sextillion possible filled Sudoku grids.