Free Online AI Sudoku Solver

Upload a Sudoku image and get instant recognition and solving. Supports Classic and Samurai Sudoku. Provides complete answers, step-by-step solutions, difficulty analysis, and technique explanations. Whether you're a beginner or an advanced player, understand the logic behind every cell placement with detailed reasoning steps.

Supports Classic Sudoku

Supports Samurai Sudoku

Solution Steps Example

Example Sudoku Puzzle

Solution Info

Sudoku Info

Sudoku Type: Classic Sudoku
Difficulty: Hard
Given Numbers: 28
Total Step Count: 55
Correct Answer:

Array Format Answer

Array

 1  [ 6, 5, 3, 1, 8, 4, 2, 7, 9 ],
 2  [ 7, 8, 9, 6, 2, 3, 5, 4, 1 ],
 3  [ 4, 1, 2, 9, 5, 7, 3, 6, 8 ],
 4  [ 2, 7, 1, 3, 9, 6, 4, 8, 5 ],
 5  [ 3, 6, 4, 5, 1, 8, 9, 2, 7 ],
 6  [ 8, 9, 5, 4, 7, 2, 1, 3, 6 ],
 7  [ 9, 4, 8, 2, 6, 1, 7, 5, 3 ],
 8  [ 1, 3, 6, 7, 4, 5, 8, 9, 2 ],
 9  [ 5, 2, 7, 8, 3, 9, 6, 1, 4 ]

Solving Methods

Single Cell Deduction: 43
Box Unique Candidate: 9
Row Unique Candidate: 1
Column-Box Reduction: 1
Row-Box Cross Reduction: 1

Solving Steps

Step 1：R7C2 = 4

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 4 can fit.

Step 2：R9C8 = 1

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 1 can fit.

Step 3：R4C8 = 8

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 8 can fit.

Step 4：R5C8 = 2

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 2 can fit.

Step 5：R3C8 = 6

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 6 can fit.

Step 6：R3C1 = 4

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 4 can fit.

Step 7：R9C1 = 5

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 5 can fit.

Step 8：R1C1 = 6

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 6 can fit.

Step 9：R9C3 = 7

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 7 can fit.

Step 10：R9C6 = 9

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 9 can fit.

Step 11：R1C2 = 5

In this box, number 5 can only be placed here — all other empty cells in the box already have 5 in their rows or columns.

Step 12：R5C2 = 6

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 6 can fit.

Step 13：R6C2 = 9

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 9 can fit.

Step 14：R2C4 = 6

In this box, number 6 can only be placed here — all other empty cells in the box already have 6 in their rows or columns.

Step 15：R3C6 = 7

In this box, number 7 can only be placed here — all other empty cells in the box already have 7 in their rows or columns.

Step 16：R1C5 = 8

In this box, number 8 can only be placed here — all other empty cells in the box already have 8 in their rows or columns.

Step 17：R3C7 = 3

In this box, number 3 can only be placed here — all other empty cells in the box already have 3 in their rows or columns.

Step 18：R1C7 = 2

In this box, number 2 can only be placed here — all other empty cells in the box already have 2 in their rows or columns.

Step 19：R5C1 = 3

In this box, number 3 can only be placed here — all other empty cells in the box already have 3 in their rows or columns.

Step 20：R4C6 = 6

In this box, number 6 can only be placed here — all other empty cells in the box already have 6 in their rows or columns.

Step 21：R8C6 = 5

In this box, number 5 can only be placed here — all other empty cells in the box already have 5 in their rows or columns.

Step 22：R5C6 = 8

In this row, number 8 can only be placed here — all other empty cells in the row already have 8 in their columns.

Step 23：R1C5

Candidates of a number in this column all point to the same box, allowing elimination of that candidate from other columns within the box.

Step 24：R5C1 = 1

Within the intersection of this row and box, a number's candidates are constrained to a single position.

Step 25：R6C6 = 2

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 2 can fit.

Step 26：R6C5 = 7

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 7 can fit.

Step 27：R5C5 = 1

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 1 can fit.

Step 28：R5C4 = 5

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 5 can fit.

Step 29：R5C9 = 7

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 7 can fit.

Step 30：R6C4 = 4

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 4 can fit.

Step 31：R6C7 = 1

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 1 can fit.

Step 32：R4C7 = 4

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 4 can fit.

Step 33：R4C9 = 5

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 5 can fit.

Step 34：R4C3 = 1

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 1 can fit.

Step 35：R6C1 = 8

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 8 can fit.

Step 36：R6C3 = 5

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 5 can fit.

Step 37：R7C3 = 8

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 8 can fit.

Step 38：R7C6 = 1

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 1 can fit.

Step 39：R7C7 = 7

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 7 can fit.

Step 40：R7C9 = 3

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 3 can fit.

Step 41：R7C4 = 2

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 2 can fit.

Step 42：R3C4 = 9

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 9 can fit.

Step 43：R1C4 = 1

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 1 can fit.

Step 44：R1C9 = 9

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 9 can fit.

Step 45：R2C5 = 2

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 2 can fit.

Step 46：R2C3 = 9

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 9 can fit.

Step 47：R2C9 = 1

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 1 can fit.

Step 48：R3C3 = 2

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 2 can fit.

Step 49：R4C4 = 3

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 3 can fit.

Step 50：R4C5 = 9

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 9 can fit.

Step 51：R8C1 = 1

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 1 can fit.

Step 52：R8C5 = 4

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 4 can fit.

Step 53：R8C7 = 8

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 8 can fit.

Step 54：R9C5 = 3

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 3 can fit.

Step 55：R9C9 = 4

All other numbers have been eliminated by the filled digits in this cell's row, column, and box. Only 4 can fit.

55 steps total · Showing first 3 steps

Answer Example

Samurai Sudoku Solver

Samurai Sudoku consists of 5 overlapping 9×9 standard Sudoku grids, forming a massive 21×21 board. Each sub-grid shares overlapping regions, significantly increasing the puzzle's difficulty. This solver supports automatic recognition of Samurai Sudoku images, accurately parsing the layout and overlap relationships of all 5 sub-grids, and delivering complete answers with step-by-step reasoning. Whether it's standard-difficulty Samurai Sudoku or high-difficulty variants, accurate solutions are guaranteed. Upload a Samurai Sudoku image and the AI instantly recognizes the 21×21 mega-board to provide detailed solutions.

Killer Sudoku Solver

Killer Sudoku adds 'cages' and sum constraints on top of classic Sudoku rules. All numbers within each cage must sum to the total indicated in the top-left corner. This means Killer Sudoku must satisfy not only the row, column, and box uniqueness rules, but also arithmetic constraints, making it significantly harder than classic Sudoku. This solver supports automatic recognition of Killer Sudoku images — the AI automatically identifies cage boundaries and sum clues, combining arithmetic constraints with logical reasoning to solve the puzzle. Upload a Killer Sudoku image and the system instantly parses the cages and sum totals, outputting the correct answer and detailed step-by-step solutions.

Frequently Asked Questions

How do I use this Sudoku Solver?

Click "View Answer" or "View Solution Steps"
Upload a Sudoku image (drag & drop, paste Ctrl+V, or click to select)
On mobile: take a photo or pick from gallery
Auto-recognizes the puzzle and returns results instantly

What information does the solver provide?

Complete correct answer (visual grid + array format)
Detailed step-by-step solution, each step includes:
- Cell position (row/column coordinates)
- Solving technique (Single Cell Deduction, Box Unique Candidate, Pointing Reduction, etc.)
- Specific reasoning explanation

What Sudoku types are supported?

Classic Sudoku (9×9)
Samurai Sudoku (5 overlapping 9×9 grids)
Killer Sudoku (with cage constraints and sum clues)
Upload any type — auto-detection and solving

What are the advantages over traditional solvers?

One-click image upload with automatic OCR recognition — no manual entry required
AI instantly outputs the complete correct answer
Ultra-detailed step-by-step solutions — understand the reasoning behind every move

How accurate are the answers?

OCR recognition accuracy: 99.99%+
300% accuracy improvement over general-purpose AI
Every solving step is precise and error-free

Free Online AI Sudoku Solver

Supports Classic Sudoku

Supports Samurai Sudoku

Answer Example

View Solution Steps

Samurai Sudoku Solver

Killer Sudoku Solver

Frequently Asked Questions

How do I use this Sudoku Solver?

What information does the solver provide?

What Sudoku types are supported?

What are the advantages over traditional solvers?

How accurate are the answers?

Free Online Sudoku Platform

Thank You!

Free Online AI Sudoku Solver

Supports Classic Sudoku

Supports Samurai Sudoku

Answer Example

View Solution Steps

Samurai Sudoku Solver

Killer Sudoku Solver

Frequently Asked Questions

How do I use this Sudoku Solver?

What information does the solver provide?

What Sudoku types are supported?

What are the advantages over traditional solvers?

How accurate are the answers?

Free Online Sudoku Platform

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