First record wins
Two emails that match after trimming and lowercasing count as duplicates. The earliest record stays. Review conflicting names or details before importing; this tool does not combine records.
A cleaner starting point
Check your intake CSV
before you import it.
Find repeated email addresses and missing fields. Review what changes, then download a cleaned copy.
Your CSV stays in this browser tab. No upload. No account. No tracking.
1. Add your records
Include a header named email. Other columns are kept. Limit: 10,000 data rows, 100 columns, and 1 million characters.
We trim spaces around emails and lowercase them, then keep the first record for each nonempty email. Different names do not override that rule. Blank emails are kept separately.
2. Review the result
- Records checked
- 0
- Duplicate records
- 0
- Rows with blank fields
- 0
- Records in export
- 0
Spreadsheet protection: cells beginning with a formula-like character are prefixed with an apostrophe in the export. This can change their displayed/imported text; review the destination's import preview.
What this check does—and what to review
Missing data stays visible
Blank fields are flagged. Rows without an email are retained separately. Suspicious email formatting is flagged, but no email address is contacted or checked for deliverability.
Your original stays yours
The tool creates a new CSV. It does not edit a file, connect to a CRM, or save your pasted data. Keep a backup and inspect the cleaned file before using it elsewhere.
Email matching is a practical heuristic. Lowercasing can merge addresses that differ only in case; plus aliases and dots are not removed. Comma-separated files with quoted fields are supported; semicolon/tab-delimited files are not.