SimpleVerifier Team · Reviewed
How do I remove duplicate emails from a list?
Lower-case and trim every address first, then remove exact duplicates on that cleaned column. Skipping the normalising step is why duplicates survive: Alice@Example.com and alice@example.com, or an address with a hidden non-breaking space, look different to a plain dedupe. Decide separately whether Gmail dot and plus variants count as one person.
Spreadsheet method
In Excel or Google Sheets, make a helper column with the cleaned address (lower-case, trimmed, with non-breaking spaces replaced), then use Remove duplicates on that column and keep the original beside it.
Gmail ignores dots in the local part and everything after a plus sign, so jane.doe@gmail.com, janedoe@gmail.com and janedoe+news@gmail.com are one mailbox. Whether to merge them depends on your goal: one send per person, or counting signups honestly.
Related questions
- Do duplicates cost extra to verify?
- Removing duplicates first keeps your list, your send counts and your verification counts clean, so do it before you upload.
Sources
Figures marked as ours come from SimpleVerifier’s own dated tests on made-up addresses, published with their data on the research page. No customer data is used, and we publish no accuracy percentage because we have no independent measurement to back one.
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