Can I Use an Underscore ( _ ) in an Email Address?

Have you noticed underscore characters in email addresses? Wondering whether they are okay to use, and how you can add them to your email address? Find here all you need to know about using the underscore ( _ ) in an email address ⤓.

Can I Use an Underscore ( _ ) in an Email Address?

Yes: the underscore _ is allowed in email user names, but not in domain names.

The underscore character (_, ASCII code 95) is a valid character anywhere in an email address’s username.

You can

• start an email address with an underscore,
  Example: _example@ladedu.com is valid.
• end your email address’s username part with an underscore and
  Example: example_@ladedu.com is valid.
• use multiple underscore characters in your email address.
  Example: _example_@ladedu.com is valid.

Not all underscores are alike: The above applies to the ASCII underscore character ‘_’. It is not true for other characters that resemble it or other methods of underlining; see below.

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Underscore in Email Address: FAQ

Can I use alternative underscore characters?

No.

Characters that look like an underscore but are not the ASCII underscore (ASCII 95, Unicode code point U+005F) are not allowed in email addresses.

Under or over: Does Capitalization Matter in an Email Address?

Examples of Underscores Not Allowed in Email Addresses

The following characters will not work as underscores in email addresses:

Can an underscore character be part of the domain name?

No.

Domains and host names cannot contain underscores. The hyphen is the only not alphanumeric character allowed in RFC 1035 (Domain Names — Implementation and Specification).

(First published April 2020, last updated January 2026)