🧹 Remove Duplicate Lines
Delete duplicate lines from a list, and sort or clean up entries instantly. Useful for email lists and data cleaning. Free, unlimited, private — works entirely in your browser.
How to use
- Paste your list into the text box — one item per line (emails, names, URLs, anything).
- Choose whether matching should be case-sensitive and whether to keep the original order.
- Click Remove Duplicates — the cleaned list appears instantly with a count of removed items.
- Copy the result or download it as a .txt file.
FAQ
Is it really free?
Yes — every tool on this site is 100% free with no limits, no signup and no watermarks.
Is my data private?
Absolutely. All processing happens locally in your browser. Your files are never uploaded to any server.
Does it keep the original order?
By default, yes — the first occurrence of each item is kept and later duplicates are dropped, preserving your list's order. You can also choose to sort the result alphabetically instead.
Is it case-sensitive?
You decide. With case-sensitive mode, 'Apple' and 'apple' count as different items. Turn it off to treat them as duplicates — useful for cleaning email lists where casing shouldn't matter.
What counts as a duplicate line?
Exact line matches after trimming whitespace. Lines that differ by trailing spaces are treated as duplicates once trimmed. Empty lines can optionally be removed too.
Can I use it for comma-separated values?
If your data is comma-separated rather than line-separated, first convert commas to line breaks (our Word Counter or a quick find-replace does this), dedupe here, then convert back if needed.
Remove Duplicates — Complete Guide
Duplicate entries creep into every list: email subscribers who signed up twice, scraped URLs, survey responses, keyword lists. The Remove Duplicates tool cleans them in one click — paste, dedupe, done — with options that handle the tricky cases.
How it works
The tool splits your input into lines, trims whitespace, and keeps the first occurrence of each unique line while dropping later repeats. Everything runs in your browser, so even a list with your customers' emails never touches a server. It handles tens of thousands of lines comfortably.
Common use cases
- Email marketing: dedupe subscriber lists before importing to avoid double-sending and hurting deliverability.
- SEO: clean keyword lists, backlink exports, and content inventories.
- Data entry: merge lists from multiple spreadsheets and strip the overlaps.
- Development: dedupe log lines, URLs, or test data quickly without writing a script.
- Research: clean survey responses and citation lists.
Getting the options right
- Case sensitivity: emails and URLs are effectively case-insensitive — turn it off. Product SKUs or codes may be case-sensitive — leave it on.
- Keep order vs. sort: keep order when sequence matters (ranked lists, timelines); sort when you want a tidy alphabetical reference.
- Whitespace: invisible trailing spaces are a classic cause of "phantom" non-duplicates; the trim option neutralizes them.
- Empty lines: remove them for a compact list, or keep them if blank lines separate meaningful groups.
Workflow tips
For spreadsheet work, copy a column, dedupe here, and paste back. For bullet-proof mailing lists, dedupe again after lowercasing everything. And always keep a backup of the original list before cleaning — deduplication is one-way.
Near-duplicates need extra care
This tool catches exact matches. For near-duplicates — "Jon Smith" vs "John Smith", or URLs with and without trailing slashes — normalize first: lowercase everything, strip punctuation, or standardize formats. A two-pass approach (normalize, then dedupe) catches what a single pass misses.
Scale notes
Browser-based dedup handles tens of thousands of lines easily. For million-row datasets, use database DISTINCT queries or command-line tools like sort -u. The logic is identical; only the venue changes.