How to play / Check your work

How to check your work on a sudoku board

By the end of this you will be able to find out whether anything you have filled in is wrong, and you will know what the check does not tell you.

Before you start: A board with at least one number filled in.

Steps

1. Open the board menu and choose "Check my answers".
2. Read the message that appears.
3. If anything is wrong, the offending numbers are highlighted on the board.
4. Correct them with "Erase" or by placing a different number.

What happens

When everything is right the app says "Nothing wrong so far. Every number you have filled in is right." When something is wrong it says how many numbers are in the wrong spot and highlights them. It reports on what you have filled in, so a clean check does not mean the board is nearly done.

If something goes wrong

The check says nothing is wrong but you are still stuck

That is the normal case and it is good news. Every board is checked before publishing, so a step is always available. Ask for a hint to learn what kind of step it is.

You want to know which numbers are missing

The check does not do that. It marks what is wrong, not what is absent.

Questions

Does checking affect my stats?

Yes. It counts as help in the same way a hint does, so a solve that used it is not recorded as unaided.

Related

• How to use a hint without spoiling the puzzleBy the end of this you will know how to ask what kind of step is available next, and what that does and does not tell you.
• How to enter numbers and use pencil marksBy the end of this you will be able to fill a square, pencil in the numbers a square could be, and take back anything you did not mean.

What this is for: read about the feature.

Last updated 2026-09-20.