Data & calculations
Contact CSV cleaner
Prepare contact data before importing it into a CRM or ad account. Map fields, handle country codes and review rows that still need attention.
Files and text are processed on your device and are not sent to the blog server. Individual tool settings are saved only in this browser.
How to use it
- Upload a CSV and select email, phone and deduplication columns.
- Select the known country for local numbers. Leave them unconverted if the country is unknown.
- Review flagged rows. Download the cleaned sheet and a separate issue list.
This validates formatting, not mailbox existence or phone ownership. Deduplication keeps the first row. Rows with empty keys are retained.
Questions and answers
How are duplicates handled?
Choose a comparison column. The first matching row is kept in full and later duplicates are removed; values from different rows are not merged. Rows with empty keys remain.
How should I choose the phone country?
Choose a country only when you know the local numbers belong to it. Adding a country code removes leading local zeros. For a mixed-country list, leave code insertion off.
Does the check confirm an email address exists?
It checks address formatting without sending mail or verifying delivery. Flagged rows remain in the cleaned table. Download a separate findings list for manual review.