Choose a difficulty level
Hard Sudoku is for solvers who want a fight: sparse starting clues and deductions that demand pencil-mark discipline and patience. Every puzzle still has a unique, logic-only solution. Play hard Sudoku online for free right here — the puzzle above loads instantly in your browser.
No ads. No sign-up. Just the game.
Pick a difficulty — easy puzzles start with more clues, hard ones with fewer.
Select an empty cell, then choose a digit from the number pad (or press 1–9 on your keyboard).
Fill every row, column, and 3×3 box with the digits 1–9, each exactly once.
Use pencil marks (press N) to note candidates, and spend a hint when you're stuck — you get three per game.
The puzzle is solved when every cell is filled and no digit repeats in any row, column, or box.
Yes — completely free, with no ads and no sign-up. Open the page and play. There is no premium tier and nothing to unlock.
No. There is no registration and no login. The game runs entirely in your browser — pick a difficulty and start filling cells.
Fill the 9×9 grid so that every row, every column, and every 3×3 box contains each digit from 1 to 9 exactly once. The pre-filled clues can't be changed; your job is to work out the rest.
Start with easy if you're new — the grid opens with plenty of clues and every step follows from scanning. Medium removes some of those givens, and hard expects pencil-mark elimination and patience.
Yes. The game runs in any modern browser — desktop, tablet, or phone — with a touch-friendly number pad. Nothing to download or install.
Yes. Every puzzle is generated with a verified unique solution, so logic alone is always enough — no lucky guesses required.