How to Check If an Email Address Is Valid

5 min read

An email address can look right and still not work. The mailbox may be closed, the domain may not exist, or the address may have a typo. Checking before you send saves you from bounces, which can hurt your sender reputation.

Quick checks you can do yourself

Look for typos in the domain, such as gmial.com or hotmial.com.
Make sure there is exactly one @ and no spaces.
Open the company's website. If the domain has no site at all, the address is suspect.
Compare with other addresses from the same company to see the usual pattern.

These catch obvious mistakes, but they cannot tell you whether the mailbox really exists.

What a proper email check tests

Format: is the address written correctly?
Domain: does the domain exist and can it receive mail?
Mail server: does the receiving server answer?
Mailbox: does that exact mailbox exist? The tool asks the mail server directly, and no email is sent to the person.

Reading the result

Passed: the mailbox exists and is safe to send to.
Failed: the address does not work. Remove it.
Unknown: the check could not decide. Some servers accept mail for any address, or refuse to say whether a mailbox exists.

An honest tool shows Unknown instead of guessing. If you see many Unknown results, read our guide on catch-all addresses before you decide what to do.

No check is perfect, and a valid address is not permission to email someone. Make sure you have a lawful reason to contact them.

Checking one address or a whole list

For a single address, a free check is enough. For a list, run the whole file through a checker, remove Failed addresses, and send first to the ones that passed.

Check which emails work

Paste or upload your list. Only Passed and Failed results use a credit. Unknown results are free.

Open the email checker