Duplicate Line Remover
Remove duplicate lines
Remove duplicate lines Runs locally in your browser
One item per line. Duplicates are dropped and the first occurrence keeps its position.
About the
The Duplicate Line Remover deletes repeated lines from a block of text, keeping the first occurrence of each line and dropping every later copy. Order is preserved, so the remaining list keeps the sequence you originally had, which matters when the list is a set of steps or a timeline. Comparison is exact: two lines that differ by a single trailing space are two different lines, so trimming whitespace first is the usual fix when the result looks wrong.
Where people use the
- Cleaning a list of email addresses or IDs before a bulk import.
- Finding how many unique values a column actually contains.
- Removing repeated log lines before pasting them into a ticket.
- Deduplicating a list of URLs collected from several sources.
How to use the
- 1
Paste your list
One item per line. Anything separated by commas or spaces needs splitting into lines first.
- 2
Trim whitespace if needed
Run the text through Text Trimmer before deduplicating. A trailing space is enough to make two identical-looking lines count as different.
- 3
Remove duplicates
The output contains each distinct line exactly once, in the order it first appeared.
- 4
Compare the counts
Counting the lines before and after tells you how many duplicates there were, which is often the actual answer you wanted.
Tips and best practices
- Always trim whitespace before deduplicating, not after.
- Sort first if you want to see the duplicates grouped together; sort after if you want the original order preserved.
- Keep the original list until you have checked the line counts, because the operation cannot be undone.
Frequently asked questions
Which copy is kept?
The first occurrence. Every later identical line is removed. If you need the last occurrence instead, reverse the list first, deduplicate, then reverse it back.
Why are two identical-looking lines still both there?
Because they are not actually identical. Invisible differences such as a trailing space, a tab, or a Windows carriage return on one line only will keep them distinct. Trim first.
Is the comparison case-sensitive?
Yes. Apple and apple are treated as two different lines. Convert the case first if you want them merged.
Can it remove duplicates within a single line?
No. This works line by line. For repeated words inside one paragraph you need a different approach.
How large a list can it handle?
It is bounded by the memory of your browser tab. Lists of tens of thousands of lines are fine; millions are not.