Clean an email list before you import it
Mailing lists collected from forms, events and old exports carry duplicates, capitalised and padded addresses, and entries that aren't email addresses at all. Upload the list and SpreadsheetFix tidies it in your browser before it reaches your email platform.
- Free up to
- 5,000 rows
- Account
- Not required
- Upload
- None
No file to hand?
Before and after
email,first_name Ana@Example.com ,Ana ana@example.com,Ana ben@example,Ben cara@example.ie,Cara
email,first_name ana@example.com,Ana ben@example,Ben cara@example.ie,Cara
1 duplicate removed. ben@example is flagged for review (no domain suffix) and listed in a separate quarantine file.
How it works
- 1
Upload your list as CSV or Excel.
- 2
Addresses are trimmed and lowercased, then duplicate rows are removed. Normalising first means “Ana@Example.com ” and “ana@example.com” are recognised as the same subscriber.
- 3
Rows with invalid addresses are flagged for review and listed in a separate quarantine file. Fix or delete them, then download the list and import it.
Why clean before importing
Most email platforms charge by the number of contacts, so duplicates cost money. Invalid addresses bounce, and a high bounce rate can hurt delivery for the whole list. Fixing both before import is cheaper than cleaning up afterwards.
What “invalid” means here
SpreadsheetFix checks that each address has the shape of an email: a name, an @, a domain and a top-level domain such as .com or .ie. It doesn't contact mail servers, so it can't tell whether a correctly formed mailbox actually exists.
Duplicates by email only
If the same person appears with different names or signup dates, open the column picker on Remove Duplicates and select only the email column. Rows with the same address are then treated as duplicates, and the first one is kept.
Questions
How do I remove duplicate emails from a list?
Upload the list above. Addresses are normalised and duplicate rows removed. To de-duplicate on the email column alone, select it in the Remove Duplicates column picker.
Does it verify that the mailbox exists?
No. It checks the address format only and never contacts mail servers, which keeps your list private.
Is it OK to lowercase email addresses?
In practice, yes. Email providers treat addresses case-insensitively, and email platforms compare them that way too.
Is my list uploaded anywhere?
No. Everything runs in your browser.