Remove duplicate lines
Paste a list — email addresses, log lines, spreadsheet rows copied as text — and this tool strips out repeated lines while you choose exactly how a "duplicate" is defined: case-sensitive or not, trimmed or not, blank lines counted or not.
- Nothing you type leaves this page
- Works offline once loaded
- Free forever, no signup
Preparing Remove Duplicate Lines for you…
Loading the tool into your browser. Nothing is uploaded — the work happens on your device.
- Lines in {{ result.totalIn }}
- Lines out {{ result.totalOut }}
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How to use this tool
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Paste your list
One item per line — or load the sample to see how the options behave.
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Set the matching rules
Choose whether to keep the first or last copy of each duplicate, ignore case, trim stray spaces, and drop blank lines.
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Copy the cleaned list
The result updates live; copy it back to your spreadsheet or script.
Questions people ask
What counts as a duplicate line?
By default, an exact character-for-character match. Turn on "ignore case" to treat Apple and apple as the same line, and "trim whitespace" to treat "banana" and "banana " (with a trailing space) as the same line too.
What is the difference between keeping the first and last occurrence?
If a line appears three times, "keep first occurrence" keeps it in the position where it first showed up and discards the later copies; "keep last occurrence" keeps it in the position of its final appearance instead. Useful when later entries in a log or export are the more up to date ones.
Does it remove blank lines automatically?
Only if you turn on "ignore blank lines" — otherwise blank lines are treated like any other line, and repeated blank lines get deduplicated the same as repeated text.
Can it sort the result as well?
Yes — the optional "sort result A–Z" checkbox alphabetises the deduplicated list after duplicates are removed, which is handy for turning a messy export into a clean, checkable list.
Is my list uploaded anywhere?
No. Deduplication runs entirely in your browser's JavaScript — there is no server endpoint on this page that accepts text, so the list never leaves your device.
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Bookmark this page — the tool keeps working offline, and your settings stay in this browser. Built by Dynamb Technologies, who make software for a living.