Are Email Addresses Case Sensitive?

Generally you can use just lower-case letters

E-Mail Concept illustration

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Every email address has two parts that are separated by the @ sign; the username and the domain from which the email account was created. Both sides typically contain both upper- and lower-case letters as well as numerals and underscores or periods. Considering how easy it is to make an error when typing an email address, you may be interested to know how important using lower-case letters versus upper-case ones really is. For example, is recipient@example.com the same as Recipient@EXAMPLE.com as far as email servers are concerned?

Does Case Matter? Yes and No

The domain name part of an email address is case insensitive, meaning the case doesn't matter. The username part, however, is case sensitive. The email address recipient@example.com is indeed different from Recipient@example.com.

Google email addresses ignore not only the letter case, but also periods. For instance, jsmithe@gmail.com is the same as j.smithe@gmail.com.

Your Message Will Likely Be Delivered

However, since the case sensitivity of email addresses can create confusion, interoperability problems, and user aggravation, some email providers and clients either fix the case for you if you type it in wrong, or ignore the case altogether. In fact, hardly any email service or ISP enforces case sensitive email addresses. What that means for you is that, even if addresses you type an address in wrong, it's still likely to be delivered.

To ensure 100 percent delivery from those who want to send you messages, create any new email addresses with all lower-case letters.