Sell more with better email & SMS

Get ecommerce-focused email & SMS marketing that makes it easier to grow your brand, get sales & build better relationships.

Drive sales on autopilot with ecommerce-focused features

See Features

Are email addresses case sensitive: A marketer’s guide

Reading Time: 8 minutes

Are email addresses case sensitive? 

This continues to be a commonly asked question, it can cause some panic if you send an email and then wonder if you forgot to capitalize a letter.

So let’s clear it up once and for all: email addresses are not case sensitive.

In this article, we’re going to explore email standards, how email services respond to capitalization, and tips to consider when making a new email address.

Are emails case sensitive?

No, email addresses are not case sensitive, so you don’t need to worry about emailing the wrong person by forgetting to include a capital letter in their name.

However, the email sensitivity of the display name depends on the email service provider. Domain names are case insensitive according to the rules governing them.  

Do capital letters matter in email addresses?

To properly answer the question, “Does capitalization matter in emails?” it’s essential to distinguish between email protocols and user perception. 

Technically, email protocols treat addresses as case insensitive. This means “[email protected]” and “[email protected]” will both reach the intended recipient.

However, the use of capitalization can influence the recipient’s perception. 

An email address with strategic capitalization, such as “[email protected],” can enhance readability and convey professionalism, especially when the address is used in business contexts. 

Conversely, random or excessive use of capital letters may appear unprofessional or spam-like, potentially affecting the recipient’s response or engagement.

Look at the examples below:

If you had a chance to send your newsletter to the two addresses, which one would you choose? 

The first, right?

Gmail is the most popular email client today. That’s why it’s common to wonder, “Do capital letters matter in emails powered by Gmail?” Additionally, are Gmail addresses case sensitive?

Don’t worry, the answer is still no. 

So if you want to include capital letters in your email address, you can. It does not have a big impact on deliverability in most cases. 

But is it advisable? 

No, we do not recommend it. It can be difficult to read and give the impression of spam to your readers, which can harm your engagement. 

Email address standards you should know

When coming up with an email address, you should ensure that you follow email address standards.

An email address is primarily divided into three parts:

These are separated by an “@” and a “.” as shown below.

email address standards scheme

Let’s look at each segment in detail.

Username standards

Anything that you write before the “@” symbol in emails is considered to be your username, which is your unique address. It’s also referred to as the prefix or local part of your address. 

Your username can contain numbers and any 64 Latin characters. You can use periods here, but they shouldn’t be the first or last characters, and they must not be consecutive. 

Domain standards

Any information keyed in after the “@” symbol in emails indicates your email server. This shows the web where to direct your email.

For the domain part, you can use Latin characters and numbers 0 to 9. The domain name must match the requirements for a hostname and must not exceed 63 characters. 

Additionally, the domain must exist in the first place and should offer an email capability. You can’t use random domains.

You could use common domains for emails like Gmail, Yahoo, etc. or incorporate your own domain names as well.

Other parts of an email address

Apart from the username and the domain, there are the following parts of an email address:

  • @ symbol – This is what makes your text an email address. Without it, the web won’t be able to place your text as an email address. It indicates the clear boundary between the unique username and the domain name 
  • .com, .net, .org, .gov, etc. – This is the top-level domain (TLD) for your domain name, and it should be the same as the one you’ve chosen for your domain
  • Display name – This is your name so that the receiver can make out who has sent the email. It’s also called the email name. It enables the recipient to know from a glance, where the email is coming from (for example: John Smith <[email protected]>)
parts of an email address

Got more questions related to email marketing? Omnisend has answers! Check out our Academy, it has all you need to know to succeed at email marketing. 

Inclusion of special characters in email addresses

You might want to use a particular username for your emails, only to realize that it already exists. 

What do you do in such a situation?

You can either change the username completely or tweak it a bit by adding a few special characters. Doing so would help you make your emails unique. 

Most email servers recognize some special characters like ! # $ % & ‘ * + – = ^ _ {} ~

special character in email address

For Gmail, your username can be 6–30 characters long, and it can be any combination of letters, numbers, or symbols. 

However, Gmail does not accept these characters: & = _ ‘ – + , 

Gmail has the tendency to ignore periods in the username too.

Apart from the special characters, you may also have to use international symbols. 

The way email services respond to capitalization

If you’re creating a new address, you might be wondering how the rules differ across different email service providers, especially regarding capitalization. Here’s how the most popular servers view it:

  • Gmail — not case sensitive 
  • Yahoo — not case sensitive 
  • Outlook — not case sensitive

This means that emails sent to [email protected] will still be delivered, just as if they were sent to [email protected]

Get started with Omnisend today & drive sales on autopilot with pre-built automation workflows

Best tips to create an email address

Some of our best tips for creating email addresses include:

  • Avoid capitalization and international symbols 
  • Make your address easy to remember
  • Improve readability with “.” or “-”
  • Don’t overuse periods
  • Avoid using numbers
  • Keep it short
  • Try to stick to English
  • Opt for well-known email service providers

1. Avoid capitalization and international symbols

Emails aren’t case sensitive. However, email communication is mostly based on Latin symbols and ASCII character encoding standards. It’s the basic text language and syntax enabling communication between devices.

If you interact a lot with people from different nationalities, then you have most likely had a chance to interact with international symbols. 

These are character sets comprising languages like Chinese, Greek, and Russian. It’s worth noting that there’s a character encoding standard known as Unicode that helps bridge the gap between International and Latin Symbols. 

However, not all providers support international symbols.

That’s why it’s crucial to avoid using international symbols as much as possible. Using them may impact your deliverability.

Similarly, try to avoid unnecessary capitalization in your email as capitalization may affect your email deliverability too, if it looks spammy.

2. Make your address easy to remember

You may have to repeatedly share your email address for business purposes, so it shouldn’t be a headache to pronounce and write.

Choose an address that’s easy to remember. 

A simpler email address would do this job for you with or without capitalization. The idea is to ensure that your customers and subscribers can easily identify who has sent the email just by looking at your email address. 

For instance, note how the below email address is generic and simple. 

example of an email address that's easy to remember

3. Improve readability with “.” or “-”

If you intend to include more words in your email address, the use of a period or hyphen would help a great deal in improving its readability. 

For example, of the three addresses below, the second and the third are more readable than the first:

4. Don’t overuse periods 

Though they make your email address more readable, some email service providers have limitations on their use.

As mentioned earlier, you can’t start or end your email address with periods, and you also can’t add them consecutively.

Using too many can make your email appear spammy like the one below. 

example of a spammy email address

Using such an email address is the perfect way to end up directly in the spam folder.

As they say, too much of something is dangerous. Periods are not an exception in this case.

5. Avoid using numbers

If your desired email username has already been taken by someone else, you can make it unique by adding numbers to it. However, this isn’t the best way forward. 

Adding numbers, especially a string of numbers, can make your email address appear spammy, like the one below.

email address with numbers

6. Keep it short and sweet

Email addresses aren’t meant to be essays. You must try to keep them short and sweet. Imagine having to send an email to the address below:

example of a long email address

Quite a mouthful, right? 

A long email address can make your potential client give up and move to the next brand.

7. Try to stick to English

Whether you’re using case sensitive emails or not, it’s important to choose the right language for your emails. 

While you may be using a different language to communicate with your audience, it’s always better to stick to English when it comes to email addresses.

Using words from a different language can alienate your recipients as the email may appear to have originated from another country.

It’s best to avoid an email address like the one below: 

email address with words from a different language

8. Opt for well-known email service providers

More than 306 billion emails are sent and received daily. 

graph with emails sent and received in billions

That’s overwhelming, isn’t it? 

To ensure that your recipients see your email as one coming from a genuine source, you should stick to popular email service providers (Gmail, Outlook, Yahoo! Mail, Zoho Mail, and iCloud Mail). Alternatively, you can create professional emails for your domain. This can further enable you to build trust among your receivers.

A spammy-looking email address would mean that people may ignore emails from you or may send them to spam. It can influence their attitude towards your content as well. And so, it’s important to create the most legitimate-looking email address that you can.  

Wrapping up

As we’ve mentioned earlier, the simple answer to “Are emails case sensitive” is no. Most email servers recognize and accept some special characters (! # $ % & ‘ * + – = ^ _ {} ~). A few like , & = _ ‘ – + are not accepted, and it’s usually best to avoid foreign symbols. Ultimately, remember to keep it short and easy to read. 


1. Is Gmail case sensitive? 

No, Gmail addresses aren’t case sensitive. Whether you type an email address in uppercase or lowercase, Gmail treats them as the same address.

2. Do periods matter in Gmail?

No, periods in Gmail addresses are ignored. So, Gmail treats ‘[email protected]’ and ‘[email protected]’ as the same email address. 

3. How many characters are allowed in an email address? 

Email addresses can have up to 64 characters before the “@” (the username part) and up to 255 characters after the “@” (the domain part). For example, a valid email address could be [email protected].

Get started with Omnisend now to take your email marketing to the next level
Bernard Meyer
Article by
Bernard Meyer

Bernard is the Sr. Director of Communications & Creative at Omnisend, with a passion for good research, helping ecommerce businesses with their marketing automation needs, and beating absolutely everyone in Mario Kart 64.