Duplicate Line Remover

The result updates as soon as you paste or change an option.

1. Paste your list into the Input box with one item per line. Email lists, keywords, URLs, product codes and log entries all work.
2. Set the tick boxes. Ignore case treats Apple and apple as the same line. Ignore surrounding spaces compares lines with their start and end spaces removed, and is ticked by default. Remove empty lines deletes blank lines entirely.
3. Read the result in the box labelled Unique lines. A note under it says how many duplicate lines were removed.
4. Press Copy to use the list, Download .txt to save it, or Use as input to continue editing.

Everything runs in your browser. Lists that contain customer emails or internal data are never uploaded or stored.

The tool reads the text line by line and keeps a record of the lines it has already seen. A line that is new is written to the output, and a line seen before is skipped. The first occurrence wins, so the output keeps the order of your list, which matters for ranked or chronological data. The kept line is the original, with its own capitals and spaces.

Take this list: apple, Banana, apple, banana, then apple with spaces around it, cherry and Banana again.

Blank lines follow the same rules. With Remove empty lines off, the first blank line is kept and later ones count as duplicates. With Ignore surrounding spaces on, a line holding only spaces counts as blank. Windows line endings are converted to plain ones in the output.

• Email marketers cleaning subscriber lists before an import. Ticking Ignore case catches a@x.com and A@x.com, and most mail providers treat these as one address.
• SEO specialists merging keyword lists exported from several tools.
• Developers and sysadmins finding unique entries in logs, IP lists or dependency files.
• Researchers compiling bibliographies or survey responses from multiple sources.
• Shop owners tidying SKU lists, tags and category names.

The remover pairs well with other list tools. Sort the unique lines with the alphabetical order tool or the number sorter, and fix irregular spacing first with the whitespace remover.

• Whole lines only. The tool compares complete lines, not words inside a line. Items separated by commas on one line need to be split onto separate lines first. Pasting a spreadsheet column gives one item per line automatically.
• Near duplicates stay. www.example.com and example.com, or a URL with and without a trailing slash, are different lines. Normalise them before you deduplicate.
• Turn Ignore case off for case-sensitive data such as passwords, hashes, tokens and many IDs.
• No sorting. The order is never changed. Sort afterwards if you want an ordered list.
• Check the count. The note under the output gives the number of lines removed. It includes blank lines that were dropped.

Because the work happens in your browser, long lists are handled in a moment, and nothing is sent anywhere.

As a worked example, imagine a merged mailing list with 5,000 rows pasted from three sources. Tick Ignore case and keep Ignore surrounding spaces on, then read the note under the output to see how many repeats were found. The kept lines are the first versions in your list, so if one source is more reliable than the others, paste it first. Finally, sort the unique list or copy it back into your spreadsheet.

The same approach suits keyword research. Merge exports from several tools into the Input box, remove the repeats, and you have a single list of distinct phrases. Run the result through the alphabetical order tool if you want to spot variants side by side, such as singular and plural forms, which the remover cannot match by itself because they are different words.