Text Tools
Remove Duplicate Lines
Delete duplicate lines from any list while keeping the original order.
Options
What is the Remove Duplicate Lines tool?
This free online tool cleans up lists by deleting repeated lines while keeping the first occurrence of each line in its original position. Paste in an email list, keyword list, or any line-based data, and it tells you exactly how many duplicates were removed and how many unique lines remain. Everything runs in your browser — no sign-up, no uploads.
How to use it
- Paste your list into the box, one item per line.
- Tick “Case-sensitive” if “Apple” and “apple” should count as different lines; leave it off to treat them as duplicates.
- Keep “Ignore empty lines” on to drop blank lines automatically.
- Click “Remove duplicates”, read the summary, then copy the cleaned list.
Key features
- Preserves the original order — only later repeats are removed.
- Optional case-sensitive matching for precise control.
- Optional empty-line removal so blank rows do not pollute results.
- Clear summary: “X duplicates removed, Y unique lines.”
- One-click copy of the cleaned list; fully private.
Real-world use cases
Email marketers deduplicate subscriber lists before sending campaigns. SEOs clean keyword lists merged from several tools. Analysts tidy survey responses and log files. Recruiters remove repeated entries from candidate name lists.
Practical tips
- Leave case-sensitivity off when merging lists from different sources — “John” and “john” are usually the same person.
- Turn it on when duplicates must match exactly, such as product SKUs or codes.
- Combine with the Sort Lines tool afterwards if you also want the list alphabetized.
Frequently Asked Questions
Does it keep the first or the last occurrence of a duplicate?
The first. The original order is preserved, and only later repeats of a line are removed.
What does case-sensitive mean here?
With it on, “Apple” and “apple” are treated as two different lines. With it off, they count as the same line and one is removed.
Are blank lines removed too?
Only if “Ignore empty lines” is ticked, which is the default. Untick it if blank lines are meaningful in your data.
Can it handle very large lists?
Yes. Lists with tens of thousands of lines process instantly in the browser. Extremely large pastes may take a moment.
Is my list uploaded anywhere?
No. Deduplication runs entirely on your device and nothing leaves your browser.