Which duplicate is kept?

The first occurrence of each line is kept and every later duplicate is removed, preserving the original order.

Can it ignore case and surrounding spaces?

Yes — enable case-insensitive matching and trim whitespace so lines that differ only by case or padding are treated as duplicates.

Is the original order preserved?

Yes. The tool keeps the first occurrence of each unique line in place, so the output follows the same order as your input — it does not sort the list.

How does trimming whitespace affect matching?

With trim enabled, leading and trailing spaces and tabs are ignored when comparing, so " apple" and "apple" count as the same line. The kept line is shown as you originally typed it.

What happens to blank lines?

You choose. Keep blank lines to preserve spacing between sections, or remove them so empty rows do not count as duplicates of each other.

Does it tell me how many lines were removed?

Yes. The result shows a kept-versus-removed count, so you can see at a glance how many duplicates were stripped from your list.

Remove Duplicate Lines

Q: Does any of my text get uploaded?

No. The whole process runs in your browser and nothing is sent to a server.

Paste a list and this tool removes repeated lines while keeping the first occurrence of each and preserving the original order — ideal for cleaning email lists, deduping logs, tidying CSV columns, and merging lists without re-sorting.

How it works

The tool reads your text line by line and tracks which lines it has already seen using a set. For each line it builds a comparison key based on your options: with case-insensitive on, the key is lowercased; with trim whitespace on, leading and trailing spaces are stripped before comparing. If the key has not been seen, the line is kept (exactly as you typed it) and the key is remembered; if it has been seen, the line is dropped. Because it walks top to bottom and keeps the first hit, the output preserves your original order. You can also choose whether blank lines are kept or removed.

Example

Input with case-insensitive and trim on:

Apple
banana
apple
  Banana
Cherry

Output:

Apple
banana
Cherry

The two later “apple” / “Banana” lines are removed as duplicates (matched ignoring case and padding), and the result reports 3 kept, 2 removed.

Option	Effect
Case-insensitive	”Apple” = “apple”
Trim whitespace	” apple” = “apple”
Keep blank lines	Preserve empty rows

The whole process runs in your browser and nothing is sent to a server.