Status messages
The status bar below the grid shows the current state. Informational messages are black, errors are red.
Enter numbers
The grid is ready for input. Scan or upload a Sudoku image or type the numbers or letters by hand.
Confidence: ... %
A scanned or uploaded image was recognized. The percentage indicates how confident the scanner is about the detected characters. Lower confidence may mean some cells may be misread — double-check the grid before solving or do a new scan.
No solutions
The puzzle has no valid solution. This usually means there is a mistake in the entered numbers. See Why does my puzzle have no solutions?
Solution 1 of ...
The puzzle has multiple solutions. Use the paging arrows to browse through them. See Why does my puzzle have multiple solutions?
No unique solution
The puzzle has more than one solution, so there is no single cell that can be determined with certainty. This can appear when you press Solve Cell. Use Solve to see all solutions instead.
Select empty cell first
You pressed Solve Cell without selecting an empty cell. Tap an empty cell first, then press Solve Cell.
Search has timed out.
The solver took too long and was stopped. This can happen with a large grid or puzzles with extra constraints.
Invalid entry on the board.
A cell contains a number outside the valid range for this grid size. See Which characters can I use?
Unsupported character set.
The entered characters do not match any known character set for this grid size. Check that you are using the correct characters. See Which characters can I use?
No camera found.
No camera is available on this device.
Camera access denied.
The browser was not allowed to access the camera. Check your browser or device permissions.
Camera resolution too low.
The camera does not meet the minimum resolution required for scanning.
Failed to capture image.
The scanner could not capture an image from the camera. Try scanning again.
Server Error while solving.
The server responded with an error. Try again later.
Server Error while scanning.
The server responded with an error. Try again later.
Server Error while uploading.
The server responded with an error. Try again later.
Failed to fetch
The server is not responding. Try again later.
Load failed
The server is not responding. Try again later.
NetworkError when attempting to fetch resource.
The server is not responding. Try again later.
Invalid image.
The uploaded file could not be read as an image. Make sure the file is a JPEG, PNG or other common image format.
Grid not found.
The scanner could not detect a Sudoku grid in the image. Make sure the full grid is visible. See How do I upload a Sudoku image?
Resolution too low.
The detected grid on the image is too small for the scanner to read the characters reliably. Use a higher resolution image. See How do I upload a Sudoku image?
Characters not recognized.
The scanner could not confidently read the characters inside the cells. The scan is rejected if the confidence is lower than 50%.