# Sudoku generator and checker

> Create bounded difficulty puzzles with uniqueness checks.

[Open tool](https://www.toolcabana.com/rn/sudoku-generator-and-checker) · [Games creative work and music](https://www.toolcabana.com/rn/category/games-creative-work-and-music)

Tool ID: sudoku-generator-and-checker. Requested language: rn. Description language: en. Complete guide translation: no; untranslated sections use English.

## Overview (en)

The Sudoku generator and checker creates new 9×9 puzzles with a verified unique solution, checks a grid you paste, or solves it. Generation targets 40, 32 or 26 clues for easy, medium or hard and prints the puzzle with its solution on a separate page. Checking reports the number of givens, whether the solution is unique and whether the grid is complete.

## Supported tasks (en)

Generates puzzles with a uniqueness check, checks givens or solves a supplied grid. Target clue count is not a guarantee of solving difficulty.

## Steps (en)

1. Paste the source into the input editor, or load the built-in example.
2. Set action, clues target.
3. Run sudoku generator and checker, review the output, then use the available copy or download controls.

## Settings

- Action (en; key: action; type: select): generate [en], check [en], solve [en]
- Clues target (en; key: difficulty; type: select): easy (40) [en], medium (32) [en], hard (26) [en]

## Limitations (en)

Printable output downloads as HTML and supports Print / Save as PDF. Date lists are capped at 366 candidate occurrences, participants at 64 for brackets and 50 for round robin, and worksheets at their visible limits. Source is processed locally.

## Example input

```text
530070000
600195000
098000060
800060003
400803001
700020006
060000280
000419005
000080079
```

## Privacy and connections (en)

This operation processes its source in your browser. Copy and download are explicit actions; source input is not saved in an account or history.

## Questions (en)

### How do I enter a Sudoku puzzle to solve or check?

Paste 81 digits row by row, using 0 or a dot for empty cells. Spaces, line breaks and grid characters like | + - are ignored. The puzzle is rejected if givens conflict in a row, column or box, or if it has no solution.

### Does every generated Sudoku have a unique solution?

Yes. Clues are removed one at a time from a full random grid, and each removal is kept only if the puzzle still has exactly one solution. If the target clue count cannot be reached that way, the puzzle keeps more clues, and the final count is reported.

### Does the clue count determine Sudoku difficulty?

Only roughly. The easy, medium and hard settings target 40, 32 and 26 clues, but fewer clues do not guarantee harder solving, since difficulty depends on which techniques are required. The generator states that clue count is not a guarantee of difficulty.

### Where is my input processed?

This operation processes its source in your browser. Copy and download are explicit actions; source input is not saved in an account or history.

### What are the input limits?

Printable output downloads as HTML and supports Print / Save as PDF. Date lists are capped at 366 candidate occurrences, participants at 64 for brackets and 50 for round robin, and worksheets at their visible limits. Source is processed locally.

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