Online Sudoku Game

Online Sudoku puts the classic number-logic puzzle in your browser: a 9x9 grid split into nine 3x3 boxes, a handful of cells already filled in, and the rest waiting for you to complete through deduction rather than guesswork.

The goal never changes — place every digit from 1 to 9 exactly once in each row, each column, and each 3x3 box. There's no clock forcing your hand, so a session can be a quick five-minute scan on an easy grid or a slow, careful pass through a harder one while you rule out possibilities cell by cell.

Controls

Click or tap a cell to select it, then click the number you want from the number pad next to the grid — a keyboard with the 1-9 keys also works. A pencil/notes toggle lets you jot down candidate numbers in a cell instead of committing to one, which is useful for tracking possibilities before you're sure.

Tips

• Scan for one number at a time across the whole grid before moving to the next — it's easier to spot every place a 5 could go than to solve strictly cell by cell.
• Use notes mode to mark every candidate in a tight box, then look for cells where only one candidate is left.
• Work the rows, columns, and boxes that already have the most numbers filled in first — they narrow your options fastest.
• Look for a "hidden single": a number that can only fit in one cell of a row, column, or box, even if that cell still shows candidates too.

Pick an easy grid for a quick logic warm-up, or a harder one when you want a puzzle that actually takes concentration to crack.