Remove Duplicate Lines Online — Free Duplicate Line Remover

Remove Duplicate Lines Online — Free Duplicate Line Remover. Remove duplicate lines or duplicate words from any text online. Case-insensitive and whitespace-aware matching, keep first or last, sort, show only duplicates, and count repeats — free and private.

Paste any list or block of text and this free tool will remove duplicate lines online instantly, keeping the first occurrence of every line in its original order.

It is a fast duplicate line remover for email lists, keyword lists, log files, CSV columns, URLs, product SKUs and code.

Choose how lines are compared: case-insensitive matching treats "Apple" and "apple" as the same, trimming ignores leading and trailing spaces, and "ignore extra whitespace" treats foo bar and foo bar as duplicates.

You can also drop empty lines in the same pass and keep the last occurrence instead of the first — handy when the newest entry of a log or export should win.

More than a basic duplicate text remover: switch the scope to words to remove duplicate words from a sentence or paragraph, show only the duplicated lines (a quick duplicate line finder) or only the lines that appear exactly once, and sort the result A→Z or Z→A with natural number ordering (item2 before item10).

Live statistics show the total, unique, kept and removed counts, and a table lists the most repeated lines with how many times each appears.

Download the cleaned text as a .txt file, copy it, chain another pass with "use result as input", or share a link that restores your text and options.

To work with comma-separated lists instead of lines, use the List Converter; to only sort, try Sort List Online.

Everything happens locally in your browser — your lists, customer emails and logs are never uploaded, so it is safe for private data and works offline once loaded.

Windows (CRLF) and Unix (LF) line endings are both handled, and there is no line limit beyond your device's memory.

Related text tools: Remove Empty Lines, List Difference & Intersection, Diff Checker, Find and Replace, Word Frequency Counter and Text Analyzer.

Frequently asked questions

How do I remove duplicate lines from a list?

Paste the list into Input text. With the default settings (Lines scope and Unique output), every repeated line is removed and the first occurrence stays in its original position. Click Copy Result or Download .txt; the stats show how many lines were removed.

How do I ignore case and extra spaces when removing duplicates?

Untick Case sensitive so Apple and apple count as the same line, keep Trim lines on to ignore leading and trailing spaces, and tick Ignore extra whitespace to treat runs of spaces or tabs as one space. The line that is kept is shown exactly as it was typed.

Can I remove duplicate words instead of lines?

Yes. Set Remove duplicates of to Words. Each word is kept only the first time it appears and the original line structure is preserved. Words are split on spaces, so punctuation counts: word and word, with a trailing comma are treated as different words.

How do I find which lines are duplicated?

Set Output to Only duplicates to list each repeated value once, or Only non-repeated to list values that appear exactly once. The Most repeated table shows up to 10 duplicates with their number of occurrences.

What does Keep occurrence First or Last do?

It decides which copy of a duplicate stays. First keeps the earliest occurrence; Last keeps the final one, which helps when later entries are more recent. You can also sort the result A to Z or Z to A, or remove empty lines.

Is my text uploaded anywhere?

No. Duplicates are removed in your browser, so lists of emails, keywords or logs are not sent to a server. Note that Copy link stores your text in the share URL.

How to use this online tool

Remove Duplicate Lines Online — Free Duplicate Line Remover is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

Remove Duplicate Lines Online — Free Duplicate Line Remover keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use Remove Duplicate Lines Online — Free Duplicate Line Remover for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.