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Remove Duplicate Lines

Delete repeated lines from lists and text, with options to ignore case, trim spaces and sort.

Runs locally — files never leave your device

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How to use Remove Duplicate Lines

  1. 1Paste your list or text into the Input box — one item per line.
  2. 2Duplicates are removed immediately; the first occurrence of each line is kept in its original position.
  3. 3Adjust the options: ignore upper/lower case, trim spaces, remove empty lines, or sort the result A–Z or Z–A.
  4. 4Copy the cleaned list or download it as a text file. The status line tells you how many lines were removed.

Remove duplicate lines from any list

Lists collected from spreadsheets, exports, logs and copy-and-paste almost always contain repeats. This tool deletes duplicate lines in one step and keeps the first occurrence of each, so your list stays in its original order. Optional settings let you treat different capitalisation as the same, ignore stray spaces, drop blank lines and sort the result. Everything runs locally in your browser, so even sensitive lists such as email addresses or customer IDs never leave your computer.

Options explained

  • Ignore case – London and london count as the same line.
  • Trim spaces – removes spaces and tabs at the start and end of each line before comparing, a frequent cause of "duplicates that won't go away".
  • Remove empty lines – deletes blank lines entirely.
  • Sort – keep the original order, or sort alphabetically A→Z or Z→A using natural, language-aware ordering.

The status line reports how many lines went in, how many unique lines came out, and how many duplicates and blank lines were removed.

Useful for

Email and contact lists. Merge sign-up lists from several sources, then remove duplicate addresses before importing them into a mailing tool. Turn on Ignore case, since email addresses are not case-sensitive in practice.

SEO keyword research. Keyword exports from different tools overlap heavily. Paste them all, dedupe and sort to get a clean master list.

Data cleaning. Get the unique values from a spreadsheet column — product codes, cities, categories — without building a pivot table.

Developers and admins. Deduplicate log lines, IP addresses, package names or file paths. Combined with the Regex Tester, you can extract values from logs first and then dedupe them here.

Tips

  • To find what changed between two versions of a list rather than removing repeats, use the Diff Checker.
  • If items are separated by commas instead of new lines, replace the commas with line breaks first (for example in your editor's find-and-replace), then paste the result here.
  • Want to count how many items remain? The status line shows it, or use the Word Counter for detailed statistics.

Frequently asked questions

Which copy of a duplicate is kept?
The first occurrence is kept and later repeats are removed, so the original order of your list is preserved unless you choose to sort.
What does "Ignore case" do?
With it enabled, lines that differ only in capitalisation — such as Apple, apple and APPLE — are treated as duplicates. The version that appears first is kept as written.
Why are some lines that look identical not removed?
They probably differ by invisible characters such as a trailing space or tab. Keep Trim spaces enabled to ignore leading and trailing whitespace. Other differences, like a non-breaking space or a different dash, are real differences in the text.
How does sorting handle numbers?
Sorting uses natural order for your language, so item 2 comes before item 10, and accented letters are sorted alongside their base letters.
Is there a limit on list size?
No fixed limit. Lists with hundreds of thousands of lines are processed in a moment, entirely in your browser.
Is my data uploaded?
No. The list is processed on your device and is never sent anywhere — useful for email lists, customer data or internal IDs.

Related tools

Diff CheckerPaste two versions of a text and instantly see what was added, removed or changed.Case ConverterChange text to any letter case — from Title Case to snake_case — and see every format at once.Word CounterCount words, characters, sentences and paragraphs as you type, with reading and speaking time.Lorem Ipsum GeneratorCreate as much Lorem Ipsum dummy text as you need — paragraphs, sentences or an exact word count.