Clean a contact list CSV

Instructions

1. Confirm you have a lawful reason to clean this file before you open it.
2. Drop the CSV. Choose the email column for the syntax check, and choose the columns that should count as the same contact.
3. Blank keys are kept apart, so empty emails do not collapse into one row.
4. Preview the flags and the rows that would be removed. Download the table on screen and, after you apply, the count-only summary.

Example

The email column is both the syntax check and the duplicate key.

email,name
ada@example.com,Ada
ada@example.com,Ada 2
,Bea
not-an-email,Cy

Ada 2 is removed as a duplicate key. Bea stays because the email is blank. Cy is flagged for syntax and stays unless you also remove invalid addresses.

What the checks mean

Email syntax means the cell looks like a name, an @ sign, and a domain. A flag is not a statement that the mailbox exists, accepts mail, or belongs to the person in the row.

Phone separators can be removed from a column you select. Letters are left in place, and no country code is added.

Duplicate contacts

Column duplicate removal keeps the first row for each key. The preview shows the matching key. Case still matters, and the comparison trims only the key.

Turn on “Keep rows whose selected cells are blank” if it is not already on. Two rows with an empty email then stay as two rows.

Limitations

• This page does not discover contacts, enrich companies, or send email.
• It does not decide that two different spellings of a name are the same person.
• You are responsible for having the right to process the file and for checking the preview.
• CSV and .xlsx up to 32 MB. The download is CSV. Save .xls as .xlsx first.