Email Address - which characters can I use?

This question, that of; "which characters can I use to construct an email address", is a very simple one, but the overall subject of email addressing, is very complex. I won't dare to encroach on it. I will, however, try to give a basic idea of the construction of an email address, and which characters you can use, the limits of such, and also, some interesting facts. An excellent article exists in Wikipedia on this subject and is the source of information for this article. The email address is made up of two parts:

• The part before the @ - is the the 'Local' part.
• The part after the @ - is the 'Domain' part.

An email address can be made-up of up to 64 ASCII characters in the 'Local' part and a maximum of 255 Characters in the 'Domain' part. The 'Domain' part of the email address is pretty much restricted to the 'hostname' of the email supplier - Gmail, Hotmail, Yahoo, etc. It can vary if you have your 'own' domain name. The 'Local' part of the email address can have these ASCII characters ...

• Uppercase and lowercase English letters (a-z, A-Z)
• Digits 0 through 9
• Characters ! # $ % & ' * + - / = ? ^ _ ` { | } ~
• Character . (dot, period, full stop) provided that it is not the first or last character, and provided also that it does not appear two or more times consecutively.

This also varies somewhat, with the "domain' host. Some hosts allow certain characters and not others. The addition of 'Quoted Strings', eg: ("JS"@example.com) is also permitted, thus allowing normally prohibited characters, but it is suggested that a host expecting to have mail delivered, refrain from using these strings in the 'Local' part.

This is where it gets 'messy' and 'individual'. The Hosts can vary what they want, will allow, and will send mail to! For example, you might have a host which allows certain characters to be present in the 'Local' part of the address, but will NOT allow you to send mail to an address which has certain characters in it! For example, Hotmail will NOT allow you to re-direct email from your Hotmail account to an address with, say, dot net (.net) in the domain part. Hotmail also, as per the Wikipedia article, for example, "...only allows creation of e-mail addresses using alphanumerics, dot (.), underscore (_) and hyphen (-), and will not allow sending mail to any e-mail address containing ! # $ % * / ? | ^ { } ` ~ ".


Google accounts mail (Gmail) will normally indicate to you, if a character is NOT allowable, when you are creating your account. From memory, there are certain characters that they do NOT allow - such as; +(/)

As per this Google article, <HERE>, they don't worry about the 'period' ( . ) in email addresses. "...When you sign in to your account, you can use any configuration of dots in the 'Username' field. So, if you originally signed up for an email, such as: 'yourusername@gmail.com', you can sign in with 'your.user.name@gmail.com'." That is great, because Google only recognises variations of your original account name! Read the article! That's one good reason (among many) for using Google mail (Gmail), too.


Keep a close eye on what you can, and can't, use. If you wish to be creative, this is a must.


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