Lists gathered from several places almost always contain repeats. Keyword exports, email addresses, URL lists, product codes and log lines all pile up duplicates once you merge two files. This tool takes a list with one item per line, keeps the first occurrence of each line and drops the rest. The original order is preserved unless you ask for an alphabetical sort, so a ranked list stays ranked.
The comparison options matter more than they look. Trimming whitespace before comparing catches items that differ only by a trailing space, which is common in spreadsheet exports. Ignoring case treats Apple and apple as the same entry. There is also a reverse mode that keeps only the lines that appeared more than once, which is the quickest way to audit which entries were duplicated and how a merge went wrong.
How to use the Duplicate Line Remover
- Paste your list into the box with one item on each line.
- Set the comparison options: ignore case, trim whitespace, and skip blank lines.
- Optionally sort the result alphabetically, or switch on Keep only the duplicates to see the repeats instead.
- Click Remove Duplicates, read the counts, then copy the cleaned list.
Frequently asked questions
Which copy of a duplicate line is kept?
The first one, in the order it appeared in your input. Every later match is discarded. If you sort the result A to Z the kept line is still the first occurrence, only the display order changes, so no data is lost in the process.
What does Keep only the duplicates do?
It flips the output. Instead of a deduplicated list you get just the lines that appeared two or more times, shown once each. This is useful for auditing merged files, finding repeated keywords, or spotting duplicate entries in an exported database column.
Why do the counts not always add up to the lines in?
If you tick Ignore blank lines, empty lines are excluded from the comparison entirely and are not counted as unique or as duplicates. The Lines in figure always shows the raw number of lines you pasted, including those blanks.
Is there a size limit on the list?
There is no fixed limit. Processing happens in your browser, so the practical ceiling depends on your device memory. Lists of tens of thousands of lines run in well under a second on a normal laptop or a recent phone.