Remove Duplicate Lines
Remove duplicate lines from a list online for free. Case sensitive or insensitive, keep the first or last occurrence — directly in your browser, nothing uploaded.
Your files are processed locally in your browser and are not uploaded to our servers.
How to use Remove Duplicate Lines
- 1
Paste your list into the box, one item per line.
- 2
Choose whether comparison is case sensitive, and whether to trim whitespace before comparing.
- 3
Choose whether to keep the first or last occurrence of each duplicate.
- 4
Copy or download the deduplicated result — the number of lines removed is shown above it.
Common uses
- Cleaning up a mailing list or contact list exported from another tool
- Removing repeated entries from a list of URLs, IDs, or keywords
- Deduplicating log lines or data pasted from multiple sources
Supported formats and limitations
Accepts text, up to one file at a time.
- Comparison is per whole line — two lines that differ by even one character (including trailing whitespace, unless "Trim whitespace" is on) are treated as different.
- The original relative order of the surviving lines is always preserved, whichever occurrence you choose to keep.
Frequently asked questions
No. Deduplication happens entirely in your browser.
No — surviving lines always keep their original relative order; only the duplicates are removed.
If a line appears more than once, "first occurrence" keeps it at the earliest position it appeared and removes the later copies; "last occurrence" does the reverse.
Yes — turn off "Case sensitive" to treat "Apple" and "apple" as duplicates of each other.
It ignores leading/trailing spaces when comparing lines, so "apple" and "apple " (with a trailing space) count as the same line.