Best Free OCR Software in 2026

There’s no exact percentage of a dot in an OMR sheet that can be detected by a scanner, as it depends upon the scanner setting and tolerance.

The percentage of a dot in an OMR sheet in CET that can be detected by a scanner isn’t fixed, as it is typically based on the scanner setting. And even partially shaded circles can be detected, but it depends on the quality of marking and scanner’s sensitivity.

Around 50-75% percentage of a dot in an OMR sheet in CET can be detected by a scanner.

An OMR scanner doesn't detect a specific percentage of a dot. Rather, it relies on a darkness threshold, typically requiring around 30-40% of a bubble to be filled.

For Windows, the recommended OCR programs capturing a specified screen region are ShareX and Capture2Text. Both these are screen-capturing tools for Windows and are open- source as well as free to use.