Play free online Sudoku puzzles on our featured Sudoku game interface. Learn Sudoku solving techniques through numerous examples with our smart Sudoku solver. Our online blank grid lets you play your own puzzles on our Sudoku game interface.

Play free online (intermediate) Sudoku puzzles on our featured Sudoku game interface. You can fill in candidates, highlight cells, undo or redo steps, check mistakes, and more.

Play free online (hard) Sudoku puzzles on our featured Sudoku game interface. You can fill in candidates, highlight cells, undo or redo steps, check mistakes, and more.

Free daily Sudoku puzzles of varying difficulties. Play Sudoku game every day to exercise our brains.

Play extremely hard Sudoku puzzles on your desktop computer with keyboard and mouse.

Play free online (extremely hard) Sudoku puzzles on our featured Sudoku game interface. You can fill in candidates, highlight cells, undo or redo steps, check mistakes, and more, so that you can apply the logic to solve the puzzles more conveniently.

Play free online (easy) Sudoku puzzles on our featured Sudoku game interface. You can fill in candidates, highlight cells, undo or redo steps, check mistakes, and more.

Play free online (very hard) Sudoku puzzles on our featured Sudoku game interface. You can fill in candidates, highlight cells, undo or redo steps, check mistakes, and more.

Classic Desktop Version - Play free online Sudoku puzzles with keyboard and mouse. Interface is featured with pencil marks, background highlights, undo-redo functions and more.

A Sudoku puzzle is typically played on a 9x9 grid. In a classic Sudoku grid (see Figure 1 below), there are nine horizontal rows R1 to R9, nine vertical columns C1 to C9, and nine 3x3 sub-grids (called "blocks") B1 to B9. Each row, each column, and each 3x3 block have nine squares (called "cells"), respectively.