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Merge Two Lists

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About Merge Two Lists

The Merge Two Lists tool compares two lists and combines them in different ways. You can find all unique items from both lists (union), show only items that appear in both lists (intersection), display items that exist only in List A, or display items that exist only in List B.

The tool supports four common set operations: Union shows all unique items from both lists. Intersection shows items that appear in both lists. A minus B shows items in List A that do not appear in List B. B minus A shows items in List B that do not appear in List A.

Simply paste your lists into the two input boxes and choose an operation. Results are generated instantly and can be copied with a single click.

This tool is useful for comparing keyword lists, email subscribers, product inventories, customer records, IP addresses, and other datasets. It helps you find overlaps, discover missing entries, and identify differences between two lists.

Everything runs locally in your browser. Your data never leaves your device, and no account, login, or installation is required.

How to Use Merge Two Lists

  1. Paste List A in the left panel — one item per line.

  2. Paste List B in the right panel — one item per line.

  3. Choose an operation: Union, Intersection, A minus B, or B minus A.

  4. Copy the result from the output panel.

Examples

Example — Union A ∪ B
Input
List A (one per line):
apple
banana
cherry

List B (one per line):
banana
date
cherry
elderberry
Output
apple
banana
cherry
date
elderberry
Example — Intersection A ∩ B
Input
List A (one per line):
apple
banana
cherry

List B (one per line):
banana
cherry
date
Output
banana
cherry
Example — A minus B
Input
List A (one per line):
apple
banana
cherry

List B (one per line):
banana
cherry
date
Output
apple

Frequently Asked Questions

What is the difference between Union and Intersection?

Union returns all unique items from both lists combined. Intersection returns only items that appear in both lists — the overlap.

What does A minus B mean?

A minus B (also called set difference) returns items that are in List A but not in List B. It shows what is unique to List A.

Is comparison case-sensitive?

By default yes. Toggle case-insensitive mode to treat 'Apple' and 'apple' as the same item during comparison.

Can I use this to find new subscribers added to an email list?

Yes — put your old list in A and the new list in B. Use B minus A to see which email addresses were added.

Can I use this to find which keywords appear in both of my campaigns?

Yes — put each keyword list in A and B, then use Intersection to find the overlapping keywords.

Does Union remove duplicates?

Yes — Union returns all unique values from both lists. If an item appears in both lists or multiple times in one list, it appears only once in the output.

Can I compare lists with more than two sets?

This tool compares exactly two lists. For more complex multi-set operations, run the tool multiple times using the output of one pass as input for the next.