6x6 Sudoku Solver

Enter any 6x6 Sudoku puzzle with 2x3 boxes and digits 1-6. Solve it instantly, step through the answer, or import a 36-character puzzle string.

6x6 Sudoku Solver: Fast Help for Smaller Sudoku Grids

Our free 6x6 Sudoku Solver is built for puzzles that use a 6x6 grid, the digits 1-6, and rectangular 2x3 boxes. Add your clues, paste a puzzle string, and the tool checks the grid before solving it in your browser.

How It Works

The solver uses backtracking with a Minimum Remaining Values heuristic. It chooses the emptiest problem cell first, tries valid digits, and backtracks when a branch breaks the row, column, or 2x3 box rules.

How to Use the 6x6 Sudoku Solver

  1. Enter clues - Click a cell and type a digit from 1 to 6.
  2. Import a puzzle - Paste 36 characters, using 0 or . for empty cells.
  3. Solve instantly - Fill the whole grid and check whether the puzzle has one solution.
  4. Use Step - Reveal one cell at a time when you want a hint instead of the full answer.
  5. Export - Copy the current grid as a compact 36-character string.

6x6 Sudoku Rules

A 6x6 Sudoku follows the same idea as classic Sudoku, but on a smaller board. Each row, column, and 2x3 box must contain every digit from 1 to 6 exactly once. The solver validates duplicates before it starts searching.

When This Tool Helps

  • Checking homework or classroom puzzles - 6x6 Sudoku is popular for learners because it is compact but still logical.
  • Finding a mistake - Enter the clues and let the validator catch repeated digits.
  • Testing a handmade puzzle - The uniqueness check tells you whether your clues lead to one answer or several.
  • Learning technique - Step mode gives a small nudge without taking the whole puzzle away from you.

Import Format

The import string is 36 characters long, read left to right and top to bottom. Use digits 1-6 for filled cells and 0 or . for blanks.

Example: 123000000123230000000234345000000345

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Frequently Asked Questions

It can solve valid 6x6 Sudoku puzzles that use digits 1-6 and 2x3 boxes. If the clues contradict each other, it reports that no solution exists.

Use 36 characters read left to right, top to bottom. Digits 1-6 are clues, while 0 or . means an empty cell.

Yes. After solving, the tool checks whether the starting clues produce exactly one solution or multiple solutions.

Yes. It is free, runs in your browser, and does not require an account.