Use Only Lower Case Characters in Your Email Address

Will your email get there if you use the wrong case?

Usually, it does not matter how you type an email address — in all uppercase (ME@EXAMPLE.COM), all lower case ( or mixed case ( Generally speaking, the message will arrive in either case.

There is no guarantee for this behavior, however. Email addresses can also react sensitively to a case. If you send an email with the recipient's address spelled in the wrong case, it might return to you with a delivery failure.

female hand writes the capital and lowercase letters on a chalk board
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First, note that there are two primary elements of an email address: the "local" or username section and the domain name, which is typically the service or website name for the account, such as or

It is most likely the "local" part of the email address, which is the section that comes before the @ sign, that is case sensitive, as domain names are case insensitive. If you experience this type of error, contact the source from which you received the email address and try to find out the correct spelling and case of the person or organization you are attempting to contact.

If you are unable to find out the correct email address from your original source, a bit of online research could help you discover it. Look for the person you want to contact on social media and reach out to request his or her email address. Alternatively, see what you can find using a people search website.

Of course, it is best not to let such frustrating situations develop. Unfortunately, email addresses are case sensitive in theory, and can — on rare occasions — also be in real internet life. Still, you can help minimize the problem, confusion, and headaches for everybody.

Help Prevent Email Address Case Confusion

To minimize the risk of delivery failures due to case differences in your email address and to make the job easy for email system administrators:

  • Use only lower case characters when you create a new email address.
  • Using periods between names or words can make them easier to read and remember. For example, if you create a new Gmail address, it could be better to choose "" instead of ""
  • Avoid unusual or whimsical spellings whenever possible. You run the risk of contacts being unable to recall how you to email you if your name is Susan Davis but your email address is ""

Creating an email address that makes sense, relates to who you are and is easy to remember could help someone else wonder whether they should use only lower case characters in your email address.