Sudoku is the calm, satisfying logic puzzle that millions solve over their morning coffee — and now you can play it free right in your browser. Fill a 9×9 grid so that every row, column, and 3×3 box holds the digits 1-9 exactly once. No downloads, no accounts, no sign-ups: pick a difficulty and a fresh puzzle with one guaranteed solution is ready in an instant.
The board starts with a set of given numbers, or clues, and your job is to fill in the empty cells. The only rule is that no digit can repeat within any row, column, or 3×3 box. Every puzzle is generated on the spot with a unique solution, so you never have to guess whether an answer is right — logic alone is enough.
Choose from three levels: Easy (40 clues), Medium (30 clues), or Expert (22-24 clues). You're allowed three mistakes before the game ends, but you get three hints per puzzle that reveal the correct answer for a random empty cell, plus pencil marks for jotting down candidates.
Desktop: Click a cell to select it, then type a number or click the on-screen numpad. Use Backspace or Delete to erase, and the arrow keys to move around the grid.
Mobile: Tap any cell to select it, then tap a number to place it. The pencil button toggles candidate notes, and the eraser clears a cell.
There's no points system here — the victory is filling every empty cell correctly. The game tracks your time, so the real goal is to finish fast and clean: your five best times for each difficulty are saved in your browser, and a timer counts every second from the moment the puzzle loads.
Sudoku became a worldwide phenomenon in the mid-2000s, though its roots stretch back to 18th-century number squares. This browser version generates every puzzle live with a built-in solver that guarantees a single solution. It loads from a single HTML file, runs smoothly on phones, tablets, and desktops, and is one of 20 free classic games on ZenClick — a quiet little challenge for whenever you need a mental reset.