Email Validator

Validate Email Addresses Online — Free Email Format Checker

Check whether an email address is correctly formatted — or paste a whole list and check hundreds at once. Every address is marked valid or invalid, with a plain-English reason for each one that fails.

How to Validate Email Addresses

Type or paste addresses into the box, one per line or separated by commas or semicolons. Results update as you type: the summary shows how many were checked, how many are valid and invalid, and how many have warnings. Use the filter to show only valid, invalid, or flagged addresses, then copy the valid list or the invalid list with one click. Addresses in the form Name <person@example.com> or with a mailto: prefix are cleaned up automatically.

What Gets Checked

The tool looks for a single @ sign, a part before it of no more than 64 characters that doesn't start or end with a dot or contain two dots in a row, and only characters that are allowed in an address. The domain must contain at least one dot, each section must be 63 characters or fewer and not start or end with a hyphen, and the address must end in a valid extension such as .com. The whole address can be at most 254 characters. Unusual forms that the email standards technically allow, such as quoted names or a bare IP address as the domain, are treated as invalid because they're almost never real.

With warnings turned on, the tool also flags likely typos in popular domains — gmial.com suggests gmail.com — addresses from well-known disposable email services, and duplicates. Keep in mind that this checks the format only. It can't tell whether a mailbox exists or can receive mail; the only way to confirm that is to send a message or ask the person to click a confirmation link. Up to 5,000 addresses are checked at a time.

Good Uses for This Tool

Cleaning a mailing list before an import, catching typos in sign-up data, checking a spreadsheet column of contacts, testing what your own form should accept, and quickly settling whether an address someone gave you was written down correctly.

Is It Actually Private?

Yes. Every address is checked in your browser — your list is never uploaded to a server or stored.