BounceLens

Remove duplicate emails from a list

Paste a list or upload a CSV and get it back with every address once. It finds exact copies and the copies a simple "remove duplicates" misses, like [email protected] and [email protected], which go to the same inbox. Free, no signup, and the list stays in your browser.

Download without duplicates keeps the first copy of every address, in your original order and spelling, and removes only the copies. Download clean list also removes invalid, risky and typo addresses. Each copy shows "Duplicate of …" or "Same inbox as …" in the Why column.

Why duplicates are a problem

Lists grow from many places: signup forms, imports, events, exports from an old tool. The same person ends up on the list two or three times. Then they get the same newsletter twice, which looks careless and is a quick way to an unsubscribe or a spam complaint. You may also pay for every copy, since most email tools charge per contact.

The duplicates other tools miss

Most duplicate removers, and Excel's Remove Duplicates, only find addresses that are spelled exactly the same. But Gmail ignores dots and anything after a +, and googlemail.com is the same as gmail.com. These all reach one inbox:

On your listSame inbox asWhy
[email protected][email protected]Gmail ignores dots and capital letters
[email protected][email protected]Everything after + is a label, the inbox is the same
[email protected][email protected]googlemail.com is Gmail's old name
[email protected][email protected]Most mail servers deliver name+label to name

BounceLens treats all of these as one person and keeps only the first copy it sees.

How to remove duplicates

  1. Paste your list above, one address per line or separated by commas. Or upload a CSV: each row is read, and every cell that holds an address is taken.
  2. Press Remove duplicates. The copies are marked in the table.
  3. Press Download without duplicates. You get a CSV with one email column, each address once.

The download has only the email column. If your file has names or other columns, use the full report to see which rows are copies, then delete those rows in your own file.

Remove duplicates in Excel or Google Sheets

If all your copies are spelled exactly alike, the spreadsheet can do it: in Excel, select the email column and choose Data → Remove Duplicates; in Google Sheets, Data → Data cleanup → Remove duplicates. Two things trip people up:

  • A space at the start or end makes two copies look different. Run =TRIM() on the column first.
  • Gmail dot and +tag copies are never found, because the text really is different. That's the gap BounceLens fills.

What else it checks in the same pass

While it removes duplicates, BounceLens also looks up every domain, so you see the addresses that would bounce anyway:

  • Broken format: a missing @, spaces, two dots in a row.
  • Dead domains that don't exist or have no mail server.
  • Typos like gmial.com, with the fix. See the email typo checker.
  • Throwaway addresses like Mailinator. See the disposable email checker.

Questions

Which copy does it keep?

The first one in your list, exactly as you wrote it. Later copies are removed, even if they are spelled differently.

Is it safe to merge +tag addresses at every domain?

Almost always. Gmail, Outlook.com, iCloud, Proton, Fastmail and most company mail servers deliver name+label to name. A few servers treat + as a normal letter, so at those, sam+a@ and sam+b@ could be two people. If that matters for your list, check the "Same inbox as" rows before you delete them.

Does it remove dots for Outlook or Yahoo addresses?

No. Only Gmail ignores dots. At other providers j.doe@ and jdoe@ can be different people, so they are kept.

Is my list uploaded anywhere?

No. Duplicates are found in your browser. To check the domains, only the domain names (like company.com) are looked up through public DNS, never the full addresses.

Is there a limit?

No signup and no daily limit. One run handles up to 20,000 addresses.

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