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Remove Duplicate Lines

Clean duplicate entries out of any list — emails, URLs, keywords, log lines. The first occurrence of each line is kept and the rest are removed.

Runs in your browser — files never leave your device

Free · No sign-upOutputs Plain text
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How to use Remove Duplicates

  1. Paste your list, one entry per line.

  2. Choose case-sensitive or insensitive matching, and whether to trim spaces.

  3. Click Remove duplicates.

  4. Copy the cleaned list — the summary shows how many lines were removed.

About this tool

Merged mailing lists, exported keyword sets and concatenated logs accumulate duplicates that are tedious to remove by hand. Paste the list and the tool keeps the first occurrence of each line, preserving your original order. Case-insensitive matching treats "Apple" and "apple" as the same entry; optional whitespace trimming catches lines that differ only by stray spaces. The result reports exactly how many duplicates were removed.

This is a common cleanup step after combining data from multiple sources — merging two mailing lists exported from different tools, or consolidating a keyword list pulled from several research sessions — where the same entries inevitably show up more than once.

Common ways people use this

  • Cleaning duplicate entries out of a mailing list merged from two different sources
  • Removing repeated keywords from a list pulled together from multiple research sessions
  • De-duplicating a list of URLs or file names before further processing

Tips for better results

  • Enable case-insensitive matching if your list might contain the same entry typed with different capitalization, like "Email@test.com" and "email@test.com".
  • Turn on whitespace trimming if the list was copied from a source that might have added invisible trailing spaces to some lines.

Frequently asked questions

Which copy of a duplicate is kept?
The first one, in its original position — the rest are removed, so your list order is preserved.
Are "Item" and "item " treated as duplicates?
Only if you enable the matching options: case-insensitive matching equates the capitalization, and trimming ignores leading/trailing spaces. Both are optional so you stay in control.
Can I deduplicate and sort at the same time?
Deduplicate here first, then paste the result into the Sort Lines tool — keeping the steps separate makes each result easy to verify.
How many duplicates can this handle in one go?
There's no practical limit — the tool processes the entire pasted list at once, since it all runs in your browser rather than being queued on a server.
Will this work on a list of email addresses or URLs?
Yes — it treats every line as a plain text entry regardless of content, so email addresses, URLs, product codes or any other list type work the same way.

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