Medium Sudoku — play online free

Medium Sudoku is where the game gets truly interesting. With only 25 to 37 numbers given at the start, empty cells outnumber filled ones, and you will need more than basic techniques to solve the puzzle.

This is the level where "naked pairs" and "pointing pairs" become essential. You will learn to spot two cells in a row or block that share the same two candidates — allowing you to eliminate those numbers from other cells. These techniques feel like real detective work and make solving deeply satisfying.

Medium puzzles are the most popular difficulty on OnSudoku. They offer the best balance between challenge and accessibility — hard enough to require focused thinking, but not so hard that you get stuck for long periods.

So far, 21,137 medium puzzles have been solved on OnSudoku, with an average time of 455 seconds. The points multiplier is 0.35.

Solving mediums comfortably? The Hard level awaits, where techniques like X-Wing and box/line reduction come into play.