What is the difference between merging and deduplicating two lists?

Merging combines both lists into one. Deduplicating removes any item that appears more than once. Merging with deduplication gives you a clean list of all unique items across both original lists.

Can I find the duplicates themselves (not remove them)?

Yes. The 'Common to both' result section shows every item that appears in both lists — those are your cross-list duplicates. You can export them as a CSV.

Remove Duplicates From Two Lists — Merge and Deduplicate Free

Paste two lists and see exactly where they overlap. Find the cross-list duplicates, get the unique items from each, and merge them into one clean deduplicated list — no spreadsheet formulas required.

Merge and Deduplicate Free → See a Live Example

List A — Team A Contacts5 items

List B — Team B Contacts5 items

Paste your lists and click to find duplicates

Live preview · Open the full tool to export the deduplicated merged list as CSV.

How to Remove Duplicates When Merging Two Lists

When you combine two lists, duplicates — entries that appear in both — clutter the merged result. Here's how to get a clean, unique merged list in seconds:

Paste your first list into List ACopy from Excel, a CSV file, your CRM, or anywhere. One item per line.
Paste your second list into List BThe two lists might have significant overlap — that's exactly what this tool handles.
Read the cross-list duplicatesThe "Duplicates (both)" column shows every item that appears in both lists — those would be duplicated if you naively merged the two files.
Get your clean merged listThe Merged & Deduplicated row below the results shows the complete union — all unique items from both lists, with no duplicates. Copy or export this directly.

When to Use This

Merge two contact listsCombine team contact exports without duplicating shared contacts. Use the union result as your merged list.
Clean mailing list mergesCombine two email newsletter databases without sending the same person two separate imports.
CRM data migrationsMerge records from two systems while spotting which ones are already in both before importing.
Inventory consolidationCombine product catalogs from two sources into one clean, unique master list.
Tag and label cleanupMerge two taxonomy lists and remove duplicate tags before importing into your CMS.
Spreadsheet mergesCombine two columns or sheets into one unique-values column without Excel formulas.

Frequently Asked Questions

How do I remove duplicates from two lists?

Paste the first list into List A and the second into List B. The "Merged & Deduplicated" section shows all unique items from both lists combined — with every duplicate removed. Export it as CSV to use your clean merged list anywhere.

How do I find which items are duplicated across two lists?

The "Duplicates (both)" column shows every item that appears in both lists — these are the cross-list duplicates. Export this section if you want a list of the overlapping items.

What if there are duplicates within a single list (not just between the two)?

Enable the "Deduplicate" toggle in the full tool to also remove duplicates within each list before comparing. The demo above handles cross-list duplicates only.

Is the comparison case-sensitive?

By default it's case-insensitive — "John" matches "john". The full tool lets you toggle case-sensitive mode if needed.

Is my data safe?

Yes. All processing happens locally in your browser. Nothing is uploaded to any server.