Remove Duplicate Lines
Clean up any list: remove duplicate lines, delete blank lines, trim spaces, sort alphabetically, reverse or add line numbers — all in your browser. Perfect for cleaning email lists and data.
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About this tool
Remove Duplicate Lines cleans up any list of text lines. It can strip out repeated lines, delete blank lines, trim surrounding spaces, sort the list alphabetically, reverse the order or add line numbers — all in one place.
It is a fast way to tidy email lists, log excerpts, keyword lists, CSV columns or any pasted data. Everything runs in the browser, so even large lists are processed instantly without uploading anything.
How to use
- Paste your list of lines into the input box.
- Enable Remove duplicates to keep only the first occurrence of each line.
- Optionally turn on trim spaces and remove empty lines to normalise the data.
- Choose a sort order — alphabetical or reversed — if you want the output ordered.
- Optionally add line numbers to the output.
- Copy the cleaned list from the output panel.
Features
- Remove exact duplicate lines while keeping the first occurrence.
- Delete empty or whitespace-only lines.
- Trim leading and trailing spaces from every line.
- Sort alphabetically or reverse the current order.
- Optional line numbering for the cleaned output.
- Handles large lists instantly, entirely in your browser.
Frequently asked questions
Is my list sent to a server?
No. All the processing — deduping, sorting and trimming — happens locally in your browser, so your data never leaves your device.
Which duplicate is kept?
The first occurrence of each line is kept and later repeats are removed, so the original order of unique lines is preserved unless you also sort.
Is the duplicate check case-sensitive?
By default lines are compared exactly as written, so differences in capitalisation or surrounding spaces count as different lines; enable trimming to ignore stray spaces.
Can I sort and dedupe at the same time?
Yes. You can combine options — for example remove duplicates, trim spaces and sort alphabetically — in a single pass.
How large a list can it handle?
Because the work is done in the browser, lists with tens of thousands of lines are processed quickly on a normal computer.