Remove Duplicate Lines — Free Online Tool
Delete duplicate lines from any list or text instantly. · No signup · Works on mobile
100% private: your data is processed in your browser. Nothing is uploaded to our servers.
How to use the remove duplicate lines
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1
Paste your list — emails, URLs, keywords, product codes, anything.
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2
Choose options: ignore case, trim whitespace, remove empty lines, sort output.
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3
Click Remove Duplicates, then copy the cleaned list. The tool reports how many were removed.
What does this tool do?
This free duplicate line remover cleans any list in one click — paste your text and every repeated line is removed, keeping the first occurrence. Options let you ignore letter case, trim surrounding spaces before comparing, drop empty lines, and sort the cleaned result alphabetically.
How does the remove duplicate lines work?
The tool splits your text into lines and passes them through a JavaScript Set, which keeps only first occurrences — an O(n) operation that handles 100,000+ lines instantly. With "ignore case" on, lines are compared lowercased but output in their original form.
Frequently Asked Questions
How many lines can this tool handle?
Comfortably 100,000+ lines. Deduplication uses a hash-set algorithm that processes lines in linear time, all in your browser's memory. A 50,000-line email list dedupes in well under a second on a typical laptop — no upload wait, no server queue.
Does it keep the first or last occurrence of a duplicate?
The first. If "apple" appears on lines 3, 40, and 90, the line 3 copy survives and the rest are removed — preserving your list's original order. Enable the sort option afterwards if you want the result alphabetized instead.
Is the duplicate line remover really free?
Yes — 100% free with no hidden charges, trial limits, or premium tiers for core features. You don't need to create an account or enter an email address. The site is supported by non-intrusive display ads, which keeps every tool free for everyone.
Is my data private when using the duplicate line remover?
Completely. The duplicate line remover runs entirely in your browser using JavaScript — nothing you type or upload is sent to our servers. When you close the tab, your data is gone. This makes it safe for confidential documents, financial figures, and personal information.
Does the duplicate line remover work on mobile phones?
Yes. The duplicate line remover is built mobile-first and works on any phone or tablet with a modern browser — iPhone (Safari), Android (Chrome), and everything in between. The layout adapts to small screens, so buttons and inputs stay easy to tap on a 375px-wide display.
Do I need to install anything to use the duplicate line remover?
No. The duplicate line remover works directly in your web browser — no downloads, no extensions, no signup. Just open the page, use the tool, and get your result instantly. It works on Windows, macOS, Linux, ChromeOS, iOS, and Android.