SudokuSolver.net is a free, browser-based Sudoku solver that analyzes your puzzle using real human-like solving techniques. Unlike simple brute-force solvers, our engine applies strategies in order from simplest to most advanced — Naked Singles, Hidden Singles, Locked Candidates, Naked Pairs, X-Wing, Y-Wing, and more — just like an expert player would.

After solving, you get a full analysis including a difficulty grade based on which techniques were actually required (not just the number of clues), a breakdown of how often each technique was used, and a step-by-step walkthrough you can replay on the grid to understand exactly how the puzzle was solved.

You can enter numbers manually using your keyboard, or upload a photo of any Sudoku puzzle — our OCR engine splits the image into 81 individual cells and recognizes each digit automatically. Use Pencil Mode to track candidate numbers, Hint to reveal one cell at a time, and Check to validate your entries for conflicts. Everything runs entirely in your browser — no data is sent to any server.

Sudoku is a logic-based number puzzle played on a 9×9 grid divided into nine 3×3 boxes. The grid starts partially filled with digits (called "givens" or "clues"), and your goal is to fill in every empty cell following three simple rules:

• RowEach row must contain the digits 1 through 9 exactly once.
• ColEach column must contain the digits 1 through 9 exactly once.
• BoxEach 3×3 box must contain the digits 1 through 9 exactly once.

No math is involved — Sudoku is purely a game of deduction and logic. A well-constructed puzzle has exactly one valid solution, and it can always be found without guessing.

The puzzle was first published in 1979 in an American magazine under the name "Number Place," created by architect Howard Garns. It was later adopted by the Japanese publisher Nikoli in 1984, who gave it the name Su Doku — meaning "the digit must be single." Sudoku became a worldwide phenomenon in 2005 when newspapers began publishing it daily, and today it is enjoyed by an estimated 100 million+ players around the globe.