Game Mode


Actions


Languages

16x16 Sudoku Solver

Enter the numbers of your 16x16 puzzle into the grid below. Use numbers from 1 to 16. Leave empty cells blank and click "Solve Puzzle"!

16×16 Sudoku Solver: Rules, Input and Limits

This solver searches a 16×16 grid for a completion in which the values 1–16 appear once in every row, column and 4×4 box. It uses backtracking in the browser and writes a compatible result into the empty cells when the search succeeds.

Enter the Large Grid Carefully

  1. Copy the original clues only, using values from 1 through 16.
  2. Remember that 10–16 are two-digit values contained in a single cell.
  3. Leave unknown cells blank rather than entering zero or candidates.
  4. Review each 4×4 box and row before selecting Solve Puzzle.
  5. Use Clear to remove every entry and start again.

A single clue placed one cell too far left or right can create a contradiction elsewhere in this large grid. Checking the transcription before solving is usually faster than diagnosing it afterward.

What the Output Means

The completed board is one configuration that satisfies the implemented 16×16 rules and all supplied clues. The tool does not provide a one-cell hint, explain deductions, grade the puzzle or identify which user-entered clue caused a deeper contradiction.

No Uniqueness Guarantee

The algorithm stops after finding a valid completion. It does not search for a second result, so it cannot certify that a handmade or lightly clued puzzle has a unique solution. Treat the output as a compatible completion, not as editorial validation of the puzzle.

When No Completion Is Found

Check for repeated values in each row, column and 4×4 box, then compare all two-digit entries with the source. If no immediate duplicate appears, one or more clues may still make the remaining cells impossible to complete.