How to Use Our Sudoku Solver

1. Enter numbers in the 9×9 grid by clicking an empty cell and typing a digit, selecting a number from the bar below the grid and clicking the cells in which you want to place it, or using the Load Game feature, which is explained below.
2. Press the Lock Board button. When it's clicked, all the cells with numbers will turn gray and you won't be able to change them. You can press Unlock Board if you need to make changes.
3. Press the Solver button. This will prompt a box with Solver Steps to appear. It includes a list of steps to solve the Sudoku puzzle with accompanying strategies and explanations. The cell the step is referencing will be highlighted in blue.
   • Click the ← → buttons to solve or unsolve individual cells, one strategy at a time.
   • Click the ⇤ ⇥ buttons to solve or unsolve the entire puzzle.

Ways to Enter Your Puzzle

You can either enter the digits manually or use the Load Puzzle option. When you click Load Puzzle, an input box will appear. You can submit your puzzle using two format options. In both formats, all 81 cells must be accounted for to load the puzzle. Digits must be entered in a continuous string. Do not add line breaks between rows.

Option 1: Givens, answers, and candidate numbers

Each cell is separated by a pipe symbol (|) and P indicates possible candidates. If there is a period (.), a 0, or nothing (||) between the pipe symbols, it means the cell is empty. For example:

1|P4569|.|5|

• 1: the first cell contains a 1
• P4569: the second cell has 4, 5, 6, 9 as possible candidate numbers
• |0|: the third cell is empty

Options 2: Givens and answers

This is the simpler format that only accounts for givens, answers, and blank cells. For example:

3.8….52

• The first, third, eight, and ninth cells in a row contain 3, 8, 5, and 2
• The remaining cells in the row are blank

Other Sudoku Solver Features

While our Sudoku Solver can give you all the answers, we also provide features to help you problem-solve.

• Hint button: This will list a strategy to solve a cell. The target cell is highlighted in green and the associated cells are highlighted in yellow, allowing you to figure out how to apply the strategy. Clicking the → button walks you through the strategy step-by-step.
• Show Possibilities button: This fills all unsolved cells with candidates. It allows you to spot patterns and find answers more easily.
• Reset button: If the Sudoku grid is locked, resetting it will clear any white cells with candidates or answers. If the grid is unlocked, resetting it will clear all the cells, leaving you with a blank 9×9 grid.
• See More Options: This area lets you change various display and puzzle settings, like highlighting cells and typing to place a number.

Improving Your Sudoku Skills

Whether you're practicing easy puzzles or have graduated to difficult puzzles, it's normal to get stuck and need a little help. The Sudoku solver teaches you both basic strategies like naked singles and advanced Sudoku strategies like X-wing.

Learning these solving techniques will help you spot patterns, make eliminations, and more quickly identify valid solutions. To master essential Sudoku techniques, read our tips section, which includes key strategies and examples.