Play Hard Sudoku on the Web
Start a free Hard Sudoku online directly in your browser. The web Sudoku board includes candidate notes, hints, undo, a timer and progress saved on this device, so you can leave and continue later without creating an account.
How to approach Hard Sudoku
Hard boards usually require more than a single scan. Keep complete candidate notes, revisit rows and boxes after every placement, and look for pairs or intersections that remove candidates elsewhere. Every puzzle has a unique solution, so guessing is unnecessary.
Prepare or advance
Warm up with Medium Sudoku, study the progression in Sudoku techniques, or attempt an Expert Sudoku when you want a longer challenge.
Hard Sudoku questions
Can I play Hard Sudoku online for free?
Yes. You can play every Hard Sudoku puzzle free in your browser. No account, download or signup is required.
What makes a Hard Sudoku difficult?
Hard Sudoku boards begin with fewer given digits than easier levels. That usually means more candidate notes, repeated scanning and elimination before the next placement becomes clear.
What is the hardest web Sudoku level I can play online?
Extreme Sudoku is the hardest level available on Play Sudoku Daily. Choose it when you want fewer clues and a longer challenge than the Hard level.