How to remove duplicates from a list (emails, keywords, product codes)

Merged exports, copy-pasted columns and keyword research almost always contain duplicates. Removing them by hand is slow and error-prone; here's a reliable method.

1. Put one item per line

If your list comes from a spreadsheet, copy the column — each cell becomes a line. If the items are buried in text (email addresses in a thread, for instance), extract them first with Extract emails, which can also de-duplicate as it goes.

2. Remove duplicates

Paste the list into Remove duplicate lines. The first occurrence of each line is kept in its original position, and the tool tells you how many repeats were removed.

Two options matter:

• Case sensitive — turn it off for emails and domains, where Anna@Example.com and anna@example.com are the same address.
• Ignore leading/trailing spaces — keep it on; stray spaces are the most common reason “identical” lines aren't detected.

3. Sort if needed

For a tidy result, pass the list through Sort lines. Natural order puts item 2 before item 10, and accented words sort next to their base letter.

4. Remove empty lines

Blank lines count as one duplicate of each other; if you'd rather drop them completely, use Remove empty lines.

Checking two lists against each other

To see what changed between two versions of a list, sort both the same way and compare them with Text compare.