Remove Duplicates

When the box is unchecked, "Apple" and "apple" count as the same line and only the first spelling is kept. When checked, lines must match exactly, including capitalization, so both spellings survive.

The first occurrence in your list is always kept, and the remaining order of your lines is preserved. Check "Sort output alphabetically" if you want the result ordered instead; sorting compares lines without regard to case.

Yes. Empty lines are always dropped during processing, no matter which options you pick, and the Original Lines and Unique Lines counters reflect the line counts after that cleanup.

It is on by default and strips leading and trailing spaces from every line. This means " hello " and "hello" are recognized as duplicates; turn it off if leading spaces are meaningful in your data, such as indented code.

No. Deduplication is simple browser JavaScript, so your list is processed in the page and never transmitted or stored. Press Ctrl and Enter together to run the tool without clicking the button.