I often work with large lists of email addresses when helping Mailchimp clients with their email marketing needs. Occasionally I need to identify unique values only in a list. For example a list of 100,000 contacts may have duplicate contacts and I need to quickly identify records where the email address isn’t duplicated.
How to Select Unique Email Addresses in Excel and Google Sheets
StepsOpen your data
=COUNTIF(A:A, A2)>1into the first cell in your “Duplicate” column (i.e. immediately under the header titled “Duplicate”). This formula assumes that column A of your spreadsheet contains the data that you want to analyze.