When you add contacts to a list, we’ll automatically scan for duplicates to make sure each email address only appears once.
However, we don’t do this across all lists in your account. If the same person’s email is on two lists, we see that as two people. We typically recommend keeping a single master list in your account so MailChimp can automatically prevent duplicates.
In this article, you’ll learn how to remove duplicate contacts from your account.
Remove Duplicates When Adding Contacts
MailChimp automatically scans for duplicates when you add or import contacts to a single list. If an address is found in an import file twice or more, we’ll only add it once. If you try to add someone who’s already on your list, we’ll prevent it to avoid duplication.
Remove Duplicates with the Combine Lists Tool
Having multiple lists in a MailChimp account can sometimes cause problems with duplicates. If you think there might be some duplicate contacts across your lists, you can combine your lists into one master list organized with groups. When you do this, we’ll automatically scan for duplicates to make sure nobody makes multiple appearances.
Find and Remove Duplicates with Excel
If you have multiple lists in your account and you want to keep things this way, that’s totally ok. The downside is that we can’t automatically find duplicate contacts. For example, if firstname.lastname@example.org is on List A and List B, MailChimp sees that as two separate people. This could contribute to your monthly bill.
To find duplicates, add all contacts to one Excel spreadsheet. Then use Excel’s Remove Duplicates button to identify and remove duplicate entries. Make a note of the duplicates you removed from your Excel file, and delete them from one or more of your MailChimp lists.