Are Email Addresses Case Sensitive?

Generally you can use just lower-case letters

Every email address has two parts separated by the @ sign: the username and the email service's domain. Usernames often contain both upper-case and lower-case letters and may also contain numbers, underscores, or periods.

Does Case Matter? Mostly No

Is recipient@example.com the same as Recipient@EXAMPLE.com as far as email servers are concerned?

The domain name in an email address is not case-sensitive, meaning it doesn't matter whether you use upper or lower case letters. The same applies to usernames, although outdated email servers can misinterpret capitalization in rare cases. For simplicity's sake, the best practice is to use only lower-case letters in a username.

Illustration of a person choosing between two email addresses, one with capital letters
Theresa Chiechi / Lifewire

Google email addresses ignore the letter case and periods. For example, jsmithe@gmail.com is the same as j.smithe@gmail.com.

Help Prevent Email Address Confusion

To minimize the risk of email delivery failures in your email address:

  • Use only lower case characters when you create a new email address.
  • Avoid unusual or whimsical spellings whenever possible. You run the risk of contacts forgetting your address if your name is Susan Davis, but your email address is "soozindvs@gmail.com."

Your Message Will Likely Be Delivered

Since the case sensitivity of email addresses can create confusion and delivery problems, most email providers and clients either fix the case if the email address is entered in the wrong case, or they ignore upper-case entries. Not many email services or ISPs enforce case sensitive email addresses.

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