Duplicate Line Remover

Remove duplicate lines from any text — instantly and free

Live preview | 100% client-side
Options
Input
0 lines
Output

These lines were removed because they were duplicates of an earlier occurrence:

Quick Tips

  • Use Swap to move output back to input for multi-pass cleaning
  • Enable case-insensitive to treat "Hello" and "hello" as duplicates
  • Toggle line numbers to prefix each output line with its number
  • Use Download to save the cleaned list as a .txt file

100% Private & Secure

All text processing happens locally in your browser. Nothing is ever sent to any server or stored anywhere. You can even use it offline.

What Is a Duplicate Line Remover?

A simple yet essential tool for cleaning up repetitive text data

A duplicate line remover scans multi-line text and eliminates repeated lines, keeping only the first occurrence of each unique entry. Whether you are cleaning up a list of email addresses, deduplicating log entries, or preparing data for import, this tool saves you the tedious work of manually hunting for repeats.

Unlike spreadsheet formulas or command-line one-liners, this tool gives you a visual, interactive experience with configurable options like case sensitivity, whitespace trimming, and optional sorting — all running entirely in your browser with zero server interaction.

Smart Deduplication

Removes exact duplicate lines while preserving the original order. The first occurrence of every unique line is always kept in place, giving you a clean list without rearranging your data.

Flexible Options

Configure case sensitivity, whitespace trimming, empty line handling, and alphabetical sorting to match your exact needs. Options apply live — no button press needed.

Instant Statistics

See exactly how many lines were processed, how many unique lines remain, how many duplicates were removed, and the percentage reduction — all calculated in real time.

How It Works

Three simple steps to clean up your text

1

Paste Your Text

Paste or type your text into the input area. Each line is treated as a separate entry. The output updates instantly as you type.

2

Set Your Options

Choose whether comparison should be case-insensitive, whether to trim whitespace, remove empty lines, show line numbers, or sort the output alphabetically.

3

Copy or Download

Copy the cleaned output to clipboard, download it as a .txt file, or swap it back to the input for another cleaning pass.

Frequently Asked Questions

Common questions about removing duplicate lines

A duplicate line remover scans your text line by line and removes any lines that appear more than once, keeping only the first occurrence of each unique line. It is useful for cleaning up lists, log files, CSV data, email lists, and any text where repetition needs to be eliminated.
Yes. By default, the tool keeps lines in the same order they appear in the input, removing only the subsequent duplicate occurrences. If you enable the Sort A→Z option, the unique lines will be reordered alphabetically instead.
With case-sensitive comparison (the default), "Apple" and "apple" are treated as two different lines. When you enable case-insensitive mode, the tool treats them as duplicates and keeps only the first occurrence regardless of letter casing.
When trim whitespace is enabled, the tool strips leading and trailing spaces and tabs from each line before comparing. This means " hello " and "hello" are treated as the same line. The output uses the original (untrimmed) first occurrence.
No. This duplicate line remover is 100% client-side. All processing happens locally in your browser using JavaScript. Your text is never transmitted, stored, or logged on any server. You can verify this by checking the Network tab in your browser's Developer Tools.
Click the Swap button to move the current output back into the input area. You can then adjust your options (for example, toggle case sensitivity or sorting) and the result updates live for another pass of cleaning.