Easy Converter

Remove Duplicate Lines

Remove duplicate lines from any list — emails, URLs, CSV rows, log entries — in a single click. Sort the output alphabetically, trim whitespace, ignore case differences, and copy a clean list ready for further processing. Works on millions of lines instantly in your browser.

How to use

  1. 1

    Paste your list

    Add one item per line. Whitespace is trimmed automatically.

  2. 2

    Pick options

    Choose whether to ignore case, sort the result and strip blank lines.

  3. 3

    Copy the unique list

    Click Copy or Download to save the cleaned list.

Technical details

Deduplicating a list is a textbook hash-set problem. For each input line we compute a normalised key (trimmed, optionally lowercased) and keep only the first occurrence. The browser `Set` data structure makes the operation O(n), which scales to several million lines on a typical laptop without breaking a sweat.

Whitespace handling is surprisingly important: a trailing space turns "user@example.com" into a distinct value, even though humans would consider them identical. The tool trims leading and trailing whitespace by default and can normalise internal whitespace to a single space if you enable strict mode.

Case sensitivity is configurable. For email addresses and domain names, case-insensitive comparison is mandatory (the local part of an email is officially case-sensitive but is treated as case-insensitive by every provider in practice). For passwords, IDs or URLs with paths, keep case-sensitive matching.

The deduplication preserves the original order of first appearance. If you also want alphabetical sorting, enable the Sort option and the tool will output the unique lines in lexicographic order using the host locale collation.

Frequently asked questions

Is the deduplication case-sensitive?
By default, no. Toggle Case-sensitive in the options if you need strict comparison.
How large a list can I process?
Several million lines on a modern device. The browser Set keeps the operation linear time.
Will the original order be preserved?
Yes, unless you enable alphabetical sorting in the options.
What counts as whitespace?
Spaces, tabs and non-breaking spaces, all trimmed from line ends by default.
Are my lists uploaded?
No. Processing is purely local — your list never leaves your browser.
Reviewed by:Easy Converter Engineering Team

This tool was tested and calibrated by our engineering team. All processing happens locally in your browser — your files and data never leave your device.