Quick answer: paste your list into our free Remove Duplicate Lines tool and it instantly filters out repeats, keeping only unique entries.
Common Uses
Cleaning email lists, deduplicating spreadsheet exports pasted as text, merging two lists without repeats, or tidying up a list of names, URLs, or keywords before using them elsewhere.
Case Sensitivity and Sorting
The tool can optionally ignore case (so "Apple" and "apple" count as duplicates), remove blank lines, and sort the result alphabetically — useful for producing a clean, presentable final list.
Frequently Asked Questions
Does this work with very long lists?
Yes, it processes lists of any reasonable size instantly in your browser.
Will it preserve the original order?
By default yes, unless you choose the sort-alphabetically option.
Is my data uploaded anywhere?
No, all processing happens locally in your browser.
✨ Try it now — free & instant
Open the Tool →Decide what counts as a duplicate
Two lines can look the same to a person but differ to a computer. For example, Apple and apple differ by capitalization, and apple followed by a space is not byte-for-byte identical to apple. Before removing duplicates, decide whether comparison should be case-sensitive and whether leading or trailing spaces should be ignored. This matters for IDs, URLs, and code, where a small difference may represent a separate value.
Preserve the order you need
A “keep first occurrence” method retains the original order and removes later repeats. Sorting first can make duplicate groups easier to review, but it changes the order of the list. For example, a list containing pear, apple, pear, plum, apple becomes pear, apple, plum when the first occurrence is kept.
For important data, keep a copy of the original list and compare the number of lines before and after. Review the removed values before overwriting a source file, especially when blank lines or whitespace may carry meaning. If the list contains private information, use a local tool that processes it in the browser rather than pasting it into an unknown service.
Example cleanup checklist
For a contact list, you may want to trim spaces and compare without case so “ [email protected] ” and “[email protected]” count as one entry. For product codes, that could be wrong if capitalization distinguishes models. Decide the rule first, then test it with a few known duplicates and values that should remain distinct. After cleanup, count the unique lines and review a sample near the start, middle, and end before using the result.