Remove duplicate lines from any list of text instantly in your browser. Case-insensitive matching, keep first/last occurrence, sort, and ignore blank lines — free, unlimited, and 100% private.
Free Online Duplicate Line Remover – Clean Any List in Seconds
Paste any list of text — email addresses, keywords, URLs, usernames, or to-do items — and this tool instantly strips out repeated lines, leaving only the unique ones. It's built for anyone who works with messy lists: marketers cleaning up email lists, developers de-duplicating log files or config values, students merging notes, or SEO professionals tidying up keyword lists. Instead of manually scrolling and deleting repeats one by one, you get a clean, deduplicated list in a single click.
You control exactly how duplicates are detected. Turn on case-insensitive matching so "Email@site.com" and "email@site.com" count as the same line, trim stray spaces before comparing, and choose whether to remove blank lines from the result. You can also decide whether to keep the first or the last occurrence of each duplicate, and optionally sort the final list alphabetically. Live stats show you how many lines went in, how many duplicates were removed, and how many unique lines came out — so you always know exactly what changed.
Who Uses a Duplicate Line Remover?
Marketers and email list managers use it to remove duplicate contacts before importing a CSV into a newsletter platform — one address can cost money on paid plans, and duplicates cause double sends. SEO specialists use it to clean keyword lists exported from multiple tools, where the same phrase often appears dozens of times. Developers use it on log file extracts, config values, IP lists, and environment variable names. Data analysts use it to prep a list before importing into a spreadsheet or database. Writers and students use it to merge research notes from multiple sources without ending up with the same citation repeated. Anyone who has ever pasted a long list and thought "there must be duplicates in here" will find this tool saves real time.
Fine-Grained Control Over What Counts as a Duplicate
Not every list needs the same dedup rules — so this tool gives you four independent controls. Keep which occurrence lets you decide whether the first or last copy of a repeated line survives; useful when the later copy has corrected spelling, or when you want to preserve the original order as closely as possible. Sort result offers A→Z, Z→A, or keeping the original order. Case-insensitive match treats "Apple" and "apple" as the same line — critical for emails and usernames where case is usually irrelevant. And Ignore leading/trailing spaces prevents a line with a stray space from being treated as distinct from its trimmed twin. Toggle Remove blank lines when you want a compact final result. Note that the tool never edits the text of the lines themselves — it only decides which ones count as duplicates — so your original capitalization, spacing, and content are preserved exactly for the copies it keeps.
Private, Fast, and Completely Free
Everything runs entirely inside your browser using JavaScript, so your list is never uploaded or stored on a server. It works instantly on Windows, Mac, Android, and iPhone, with no sign-up and no limit on how many times you use it or how large your list is. Because nothing leaves your device, it is safe for confidential data — email lists, internal URLs, log extracts, and anything you would not want to paste into a cloud service.