There is no hard limit. The tool runs locally in your browser, so it can handle millions of lines as long as your device has enough memory.

Trimming removes invisible spaces and tabs at the start and end of a line. Enabling this ensures that "Item A " and " Item A" are treated as the same duplicate line.

You can choose to remove all empty lines using the options panel. If unchecked, multiple empty lines will be reduced to a single empty line.