Each row, column and 3 by 3 box holds the digits 1 to 9 one time. Fill the grid as fast as you can.
Your best – 3 mistakes end the run
or press Space
Type a digit in the selected cell. N notes, Z undo, Backspace erase
Rules & what counts
Medium Sudoku: Play Free Online
A medium Sudoku on the classic 9 by 9 grid. Each row, each column and each 3 by 3 box must hold the digits 1 to 9 one time.
A medium puzzle starts with 27 to 32 digits. At least one step needs you to compare two rows, columns or boxes: a locked candidate, or a pair of cells that share the same two digits.
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.
How to play
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.
What counts in this quiz
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.
A run that ends with three mistakes is not saved.
What's not included, and why
The clock does not stop when you leave the page or change tabs.
There are no hints.
A run under 60 seconds is not saved.
Good to know
A locked candidate: when a digit can only go in one row of a box, that digit cannot go anywhere else in that row.
A naked pair: two cells of a row with the same two candidates take those two digits between them, so no other cell of the row can hold them.