B2B Marketing Team

Are Email Addresses Case-Sensitive?

I trust that in case you are studying this article, then you surely have at least one email address. But have you ever wondered by yourself the question ‘Does case matter in email addresses?’

The answer might be yes or no, but first things first.

An email address is just a unique identity of an email account. An email account is composed of 2 parts :
first, the username that is written first followed with the symbol @
and, the second component, which is the domain name.

Some people capitalize the primary letters of their email addresses. However, does the letter case play a role in sending a mail?

To put matters in perspective, read along.

Does CAPITALIZATION Matter In Email?

The short answer to whether or not email capitalization matters is a straightforward ‘No’. This is due to the fact that the domain name that’s a part of an email address is classified as insensitive everywhere on the internet. Therefore, it is irrelevant if you write the domain name in capital letters or not.

Also, there’s no issue if you capitalize the initial part of your email address, also referred to as the username. The cause for this, is that initially, usernames were categorized as sensitive, but after several revisions to the email protocol, they have been classified as insensitive.

However, keep in mind that the classification of usernames is not applicable across the board due to the fact that there are a few servers that comprise separate mailboxes for the same email address but different forms of capitalization.

The good news for you is that these are very uncommon instances and caps now no longer matter in Gmail which is widely used anyway.

Are Email Addresses Case-Sensitive?

You must be aware that email addresses aren’t case-sensitive. However, consider this recommendation carefully.

The cause for this is that you might end up finding an outdated server or software with the which is not capable of interpreting capitalization in the right manner. But do not worry, most of the email servers today are able to handle capital letters in an email address accordingly.

Even then, it would not be advised to capitalize your email address.

How Can Word Case Improve Email Open Rate?
The word case used has the capacity to enhance your email open rate according to a study conducted by Pinpointe. It indicates that once your personal name is mentioned in your email address, your email open rate has a chance of increasing up to almost 35%.

Another reason why you need to deal with word case with caution is that HubSpot claims, a little over 40% of your readers may notice your name before deciding on whether to open your email or not.

Therefore, it is certainly established here that word case does impact your email open rate to a large extent.

Email Subject Best Practices
Your email subject best practices need to include the ability to set the right expectancies of your readers, apart from capturing their interest to keep reading. Another good practice would be to provoke the thought process of the person reading the email.


To summarize, in most cases, email capitalization does not matter. However, a few older servers would possibly have different email addresses registered with different capitalization but the same content.

Use an identical capitalization pattern in all situations, to ensure that you send the email to the right person.

10 Responses

Leave A Comment

Your email address will not be published. Required fields are marked *