Remove Duplicate Lines
Paste a list to strip out repeated lines. The first occurrence of each line is kept, so the original order survives.
Everything runs in your browser, so even long lists stay private and the tool works with the network switched off.
How to use
- 1Paste your list into the box.
- 2Optionally trim spaces around each line, or drop blank lines, before comparing.
- 3Turn off case sensitivity if “Apple” and “apple” should count as the same line.
- 4Copy the deduplicated list — the first occurrence of each line keeps its original position.
Frequently Asked Questions
Does it keep the original order?
Yes. The first time a line appears it is kept in place; later copies are removed. If you want the result sorted as well, run it through the sort tool afterwards.
What does case sensitive mean here?
With it on, Apple and apple count as two different lines. With it off, they are treated as the same and only the first is kept.
Why trim spaces around lines?
Because a line with a trailing space looks identical but is technically different. Trimming catches those near-duplicates, which are extremely common in lists copied out of spreadsheets.
How many lines can it handle?
Hundreds of thousands. Deduplication uses a hash set, so it stays fast even on very large lists — the practical limit is your browser memory.
Can I see which lines were duplicated?
The counts tell you how many lines went in and how many unique ones came out, so the difference is the number removed. The tool keeps the first occurrence and drops the rest.
Does it match lines that differ only by trailing spaces?
Not unless you turn on trimming. With trimming off, “apple” and “apple ” are different lines — which is usually not what you want in a pasted list, so leave it on.