Does it treat "Apple" and "apple" as the same line?

Only if you turn on "ignore case". By default the comparison is exact, because for things like case-sensitive IDs or passwords a case-insensitive match would silently discard real data.

What about lines that differ only in trailing spaces?

Turn on "trim whitespace". It strips leading and trailing spaces before comparing, and the trimmed version is what appears in the output.

What happens to blank lines?

An empty line is compared like any other line, so the first one stays and every later empty line is removed as a repeat. A line holding only spaces counts as different unless "Trim whitespace" is on, and "Remove blank lines" drops both kinds entirely.

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Remove Duplicate Lines — free, and it runs in your browser

Strip repeated lines from a list, optionally ignoring case.

The first occurrence stays where it was — deduplicating never reshuffles your list.
Optionally ignore case and surrounding whitespace when deciding what counts as a duplicate.
Reports how many lines were removed, so you can sanity-check the result.

Ignore caseTreats "Apple" and "apple" as the sameTrim whitespaceIgnores leading and trailing spacesRemove blank linesDrops empty lines entirely

Your list

Your listTab indents · Esc then Tab to leave1 line

Result

Deduplicated list (read only)1 line

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0 bytes
Of your files or text uploaded — this tool runs in the tab
No queue
The work happens in this tab, not in a line behind other users

Three steps, nothing to install

Remove Duplicate Lines in three steps

Paste your list
Emails, URLs, IDs, log lines — anything one-per-line.
Choose what counts as a repeat
Decide whether case and trailing spaces matter. The first occurrence of each line is the one that is kept.
Take the clean list
Copy it out, with a count of exactly how many duplicates were dropped.

Why use Remove Duplicate Lines

Order is preserved
The first occurrence stays where it was. Sorting the list to deduplicate it is faster and destroys the sequence, which is rarely what you wanted.
Exact, not approximate
The numbers on screen are measured from your actual input rather than estimated, so you can act on them without checking elsewhere.
Your text stays in the page
What you paste is not transmitted or stored, so an API response full of customer records, a token or an internal query never leaves your machine.

Frequently asked questions

The first one. Everything keeps its original order, so the list is deduplicated without being reshuffled. If you want it ordered as well, run the result through the sort tool.

Deduplicating a list

Removing repeated lines is the sort of thing a spreadsheet can do but rarely without a fight. Paste the list here and it happens as you type, with the original ordering preserved — the first occurrence of each line stays where it was.

The three options exist because “duplicate” is not one definition. Two lines that differ only in capitalisation are duplicates in a list of email addresses but not in a list of API keys. Two lines that differ only in trailing whitespace are almost always duplicates, but the whitespace is invisible so the problem is hard to spot. Turn on whichever rules match your data.

Next steps

To put the deduplicated list in order, use sort lines alphabetically. To see what changed between two versions of a list, the text compare tool shows a line-by-line diff.

Sort Lines Alphabetically
Sort a list of lines A–Z, Z–A, or by length.
Text Compare
Diff two blocks of text and highlight every addition and removal.
Reverse Text Generator
Reverse text by character, by word or by line.
Find Frequent Words
Rank the most common words in a text to check keyword density.
Text to Slug
Turn a title into a clean, URL-safe slug.
Random Text Generator
Generate random strings from a character set you choose.

70 tools, none of which want your file

Everything this tool does happens in the page you are looking at. No account, no upload, no watermark.

Browse all tools Read the guides

Remove Duplicate Lines in three steps

Paste your list

Choose what counts as a repeat

Take the clean list

Why use Remove Duplicate Lines

Order is preserved

Exact, not approximate

Your text stays in the page

Frequently asked questions

01Which duplicate is kept?

02Does it treat "Apple" and "apple" as the same line?

03What about lines that differ only in trailing spaces?

04What happens to blank lines?

Deduplicating a list

Next steps

Often used alongside

More tools

70 tools, none of which want your file