Email, Messaging, & Video Calls Email 297 297 people found this article helpful Are Email Addresses Case Sensitive? Generally you can use just lower-case letters by Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated on November 09, 2019 reviewed by Jerrick Leger Lifewire Tech Review Board Member Jerrick Leger is a CompTIA-certified IT Specialist with more than 10 years' experience in technical support and IT fields. He is also owns an IT firm in Texas serving small businesses. our review board Article reviewed on Mar 04, 2020 Jerrick Leger Email Yahoo! Mail Gmail Tweet Share Email 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-case and lower-case letters and may contain numbers, underscores, or periods. It's easy to make an error when typing an email address, and it's important to use the proper lower-case and upper-case letters. Does Case Matter? Yes and No Is email@example.com the same as Recipient@EXAMPLE.com as far as email servers are concerned? The domain name in an email address is case insensitive, meaning the case doesn't matter. The username, however, is case sensitive. The email address firstname.lastname@example.org is different than Recipient@example.com. However, the email address recipient@EXAMPLE.com is the same as email@example.com. Theresa Chiechi / Lifewire Google email addresses ignore the letter case and periods. For example, firstname.lastname@example.org is the same as email@example.com. Your Message Will Likely Be Delivered Because the case sensitivity of email addresses can create confusion and interoperability problems, some email providers and clients either fix the case if the email address is typed wrong or ignore the case. Not many email services or ISPs enforce case sensitive email addresses. This means that if the address is typed wrong, it's likely to be delivered. To ensure delivery from those who want to send messages to you, create new email addresses with all lower-case letters.