In short: Removing duplicate lines keeps only the first occurrence of each line in a list, optionally ignoring letter case and surrounding spaces, and reports how many duplicates were removed.
About Remove Duplicate Lines
Combining two mailing lists, cleaning up a keyword export or tidying a log file usually leaves you with repeated lines. Spreadsheet de-duplication works but takes several clicks; here you paste, and the unique lines appear immediately in their original order.
Options control what counts as a duplicate: with Ignore case, Ana@Example.com and ana@example.com are treated as the same line; with Trim spaces, leading and trailing spaces are ignored. The first occurrence is always the one kept.
How to use Remove Duplicate Lines
- Paste your list, one item per line.
- Choose whether to ignore case, trim spaces, drop empty lines or sort.
- Copy or download the unique lines. The message shows how many duplicates were removed.
Examples
1,200 lines from two exports with 180 overlapping addresses → 1,020 unique lines, original order kept.
Apple / apple / APPLE / pear with Ignore case → Apple / pear.
Frequently asked questions
Which copy of a duplicate is kept?
The first one. Later repeats are removed, so the original order is preserved.
How many lines can it handle?
Hundreds of thousands of lines are fine; it uses a hash set, so it is fast even for large lists.
Can I see which lines were duplicated?
The message reports how many duplicate lines were removed and how many distinct values repeated.
Is my text uploaded?
No. Everything runs in your browser. You can check this yourself: open your browser’s developer tools, switch to the Network tab and use the tool — no request carries your input.
Updated November 2026 · Free, no signup · How we build and test tools