Validate Email Addresses in Excel Files Online
Validate email addresses in Excel files directly in your browser. Add a boolean column flagging valid and invalid emails, or filter to show only invalid rows — no upload required.
About this tool
Check every email address in a Excel file against RFC 5322 format rules and add a boolean validity column. Quickly separate well-formed addresses from malformed ones before importing into a CRM, sending campaigns, or loading into a database. No emails are sent — validation is purely structural and runs entirely in your browser.
Frequently Asked Questions
What does the Excel email validation tool check?
It checks the structural format of each email address: exactly one @ sign, a valid local part before the @, a valid domain with at least one dot, and no illegal characters — following RFC 5322 rules. It does not send test emails or verify that the mailbox actually exists.
Can the tool fix invalid emails in a Excel file as well as flag them?
The tool flags and reports invalid addresses — it does not auto-correct them. Export the invalid rows, correct them with the Find & Replace tool, then merge the corrected rows back using the Merge tool.
What output does the Excel email validator produce?
The tool adds a boolean is_valid column alongside all existing columns. All non-email columns are preserved unchanged for every row, so you can filter or sort by the validity flag without losing any data.
Is my data private?
Yes — completely. Your file is never uploaded to any server. Everything runs locally in your browser using WebAssembly — processing happens entirely inside your tab. Once you close the tab, nothing is retained.
What is the maximum file size?
The free limit is 50 MB. For larger files, performance depends on your device's available memory — most modern machines handle 500 MB to 1 GB comfortably.
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