Do CAPITAL LETTERS Matter in Email Addresses? Answer: NO (But They Help)
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Do CAPITAL LETTERS Matter in Email Addresses? Answer: NO (But They Help)
Posted October 3, 2017 in Tech Tips

How many times has this conversation happened to you?

Person One: “My email address is

Person Two: “Oh. Is that all in lower case or do I need to use capital letters?”

How do you answer?

How should you answer?

The correct answer is -- drumroll, please -- “Capital letters don’t matter. Big letters or little letters, they're all the same when it comes to email addresses.”

Take a look at our last “tech tip” about the infinite number of disposable and sortable addresses you can create in each of your Gmail accounts on Kiwi for GmailIn it, you’ll see examples of many email addresses.

And you might notice, just as in the illustration above, the email addresses in that blog post use capital letters in several different ways. Some use no capital letters. A few use all capital letters. Some have a mix of upper-case and lower-case letters.

Are there rules to govern this? As Person Two asks in the dialog above, “Do I need to use capital letters?”

Well, no … and yes. On the Internet, capital letters and lower-case letters are all the same in the arena of email. Computer servers do not distinguish between upper-case and lower-case letters in email addresses. “” and “” and “” will all go to the exact same inbox.

So why use capital letters?

Because of a couple things that do not matter to the Internet computers. Those couple of things are a pair of human eyes.

Capital letters, used well, help human eyes distinguish words. That’s why, in English and many other languages (but not all), capitalization is used to begin a sentence. It’s a cue that a new thought is beginning. Likewise, capital letters in proper names help cue us to the fact that the noun which is really a name is something special, attached to a person, or an institution, or a business.

Capital letters help human eyes see where words begin when letters are strung together.

Let’s look at the sentence just above if we didn’t use spaces to set off the words. It would be:


Since the Internet cannot handle spaces in email addresses (the underscore, or “_”, is the best substitute available), the wise alternative is to capitalize each word. Such as:


That last example was more readable than the iteration before it, right?

That’s why capital letters help when you give your email address to others, especially in writing on a business card, stationery, or on a web site.

The capital letters make no difference to the Internet. But to human beings, capital letters help us see the words which letters form. That’s why “” is so much better than “,” or even “MYNAME@MYCOMPANY.COM.”

The suggestion from Zive and Kiwi for Gmail is to use capital letters in email addresses, stationery, business cards, and other print materials in a sparing way to help human beings see the words inside your email address, such as: “”

And when someone asks you if capitalization matters in your email address, your answer might be: “No, it doesn’t matter at all to the technology of the internet. I use capital letters to help real people see the words in my email address. It’s not necessary, but it’s very helpful.”

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