Tip: turn on Notes to pencil in candidates, and tap a filled number to highlight all of its matches.
Sudoku is a logic puzzle played on a 9×9 grid split into nine 3×3 boxes. Some cells start with clue numbers. Your job is to fill in the rest so that every row, every column, and every 3×3 box contains the digits 1 through 9 exactly once. There is no arithmetic and no guessing — every puzzle here has a single solution reachable by logic alone.
Every puzzle is generated fresh and verified to have exactly one solution. Easy and Medium fall out from straightforward scanning. Hard and Expert leave fewer clues and demand candidate tracking and chains of deduction. Your fastest clean solve for each level is saved in your browser, along with any puzzle you leave unfinished.
How do I play Sudoku? Fill every row, column, and 3×3 box with the digits 1–9, each used once. Click a cell, then a number.
Is Sudoku free? Yes — no signup, no downloads, no installs.
Does every puzzle have one solution? Yes — each is generated and checked to be uniquely solvable with logic, never guessing.
Are my best times saved? Yes — your fastest time per difficulty and your current puzzle are stored locally in your browser.