Tap a cell, then a number. Use ✕ (or 0) to erase. Keyboard 1–9 works too.
How to play Sudoku
Fill the 9×9 grid so that every row, every column and every 3×3 box contains the digits 1 through 9 exactly once. The pre-filled grey cells are your clues; the rest is logic. Our generator builds a fresh puzzle every time and guarantees it has exactly one solution, so you never need to guess — every puzzle can be solved by pure deduction.
Tap an empty cell, then tap a digit on the number pad (or press 1–9 on your keyboard). Tap a filled cell to highlight every occurrence of that digit — handy for spotting where a number can and cannot go. The Check button marks any mistakes in red without spoiling the rest of the puzzle.
Tips for getting better
- Start with the digits that already appear most often on the board — they have the fewest possible homes left.
- Scan one 3×3 box at a time and ask: which digits are missing here, and which rows or columns already rule them out?
- If a cell has only one possible digit, fill it immediately — each placement unlocks new deductions elsewhere.
- On Hard, look for pairs: two cells in a unit that can only hold the same two digits eliminate those digits from the rest of the unit.
Easy puzzles leave 43 clues, Medium 35 and Hard 29 — a gentle morning coffee, a proper think, and a real challenge.