Play Sudoku Online - Free Sudoku Puzzle Game | OneStepKit
Play free Sudoku online in your browser with adjustable difficulty, notes, mistake tracking, AI solving, and mobile-friendly controls. Learn Sudoku rules and strategies.
Sudoku Quantum
Solve the logical grid constraints. Keep mistakes under 3 to clear the chamber.
Interactive How to Play
Sudoku Backtracking & Drafting Guide
Fill the 9x9 grid so that each row, column, and 3x3 box contains digits 1-9 without duplicates. Use draft notes to pencil possibilities, or visualize the backtracking solver as it searches. Side keypads are available on desktop and mobile for comfortable clicking! In Challenge Mode, complete the game in under 3 minutes with 0 mistakes!
Sudoku online
Play Sudoku Online for Free
Play a free Sudoku puzzle online in your browser with adjustable difficulty, mistake tracking, notes mode, and an optional AI solver. The board is designed for both desktop and mobile play, so you can solve Sudoku without installing an app.
How to Play Sudoku
Fill every empty cell with a digit from 1 to 9. A digit can appear only once in each row, each column, and each 3x3 box. Start with cells where the available candidates are easiest to eliminate, then work across the related row, column, and box.
Sudoku Difficulty Levels
Use the level selector to move from easier Sudoku puzzles toward harder challenges. Higher levels require more candidate tracking and deeper deduction, while Challenge mode adds a time limit for players who want extra pressure.
Sudoku Rules and Solving Strategy
The core Sudoku rules are simple: numbers 1 through 9 must be placed without repetition in every row, column, or 3x3 subgrid. A useful beginner strategy is to scan for missing numbers, mark candidates with Notes Mode, and look for a number that has only one legal position in a row, column, or box.
When a puzzle becomes difficult, avoid guessing too early. Track candidates, compare intersecting units, and use elimination step by step. The built-in AI Solve option can also demonstrate a backtracking solution path in the casual mode.
Sudoku on Mobile and Desktop
On desktop, you can select cells and enter numbers with the on-screen keypad or number keys. On phones and tablets, the dedicated number pad and note controls provide larger touch targets for comfortable Sudoku play. Your active puzzle stays inside the game interface instead of requiring a separate app.