Valid And Invalid Domain Name Characters (-,@,&,.,_) In A Table

You are going to register your first domain name and you wonder if you can add characters such as an underscore, a hyphen, or an ampersand. I have created a complete table with all the valid and invalid domain name characters.

Keep reading even after the table for some real-life examples with domains that use special characters and when it is a good idea to use them. You will also find out why we can’t use all the special characters.

What Characters Are Valid in A Domain Name?

When you register a new domain name you can use any English letter and any number. You can also use a hyphen (-) but not at the start or the end of a domain name. You can not also use 2 hyphens in a row in the third and fourth positions.

When I talk about a domain in the above case, I refer to the second-level domain that comes just before the .com, .net, .org, etc (these are top-level domains). This part must be unique under a top-level domain. For example, there can not be 2 different sites with the domain buycompanyname.com but it is perfectly ok for buycompanyname.net and buycompanyname.org to exist.

Here are some examples of valid domain names:

1980enjoysun.com , grow-up-fast.com, comecloser2earth.com, 3333-22222.net, buycompanyname.com.

Which Characters Are Not Allowed in Domain Names?

Most of the special characters except hyphens are not allowed in a (second level) domain. Things like an underscore, period, comma, apostrophe, exclamation mark, question mark, ampersand, bracket are not valid options.

Some special characters are not allowed in a domain name because they are “reserved” for other cases. For example, a question mark indicates that certain values are assigned to certain parameters. In the below screenshot I did a search on Linkedin with the keyword “logistics”.

After that search, i see only results relevant to the keyword “logistics”. Don’t confuse a url with a (second-level) domain. As you can see in the above screenshort there are many special characters, even some underscores!

The URL is everything you see here: https://www.linkedin.com/search/results/all/?keywords=logistics&origin=GLOBAL_SEARCH_HEADER (for some reason google chrome hides “https://www.”).

“linkedin” is the second level domain and “com” is the top-level domain!

Numbers In Domain Name Good or Bad?

It is not advised to use numbers in a domain name. They can lead to confusion from the user’s perspective. For example, users can type “four” or “for” instead of “4”. That way you will lose some traffic to other domain names.

Another common confusion comes with “2” when a user can type “two” or “to” instead. Despite the previous cases, sometimes it makes sense to use numbers in a domain when numbers have an underline meaning.

I would like to mention that search engines (google,bing etc) will not penalize your site for using numbers. You can rank on search engines if your content is good or/and you promote your website well. I have some examples of domains with numbers below:

247 IT International – 247itinternational.com . 247 represents here 24 hours per day, 7 days per week. Companies usually want to indicate that their services or content are available all the time.

Finance 101 – finance101.com . The 101 (“one-o-one”) is used for introductory courses at a beginner’s level in colleges and other education entities.

Blend360 – blend360.com . The number 360 is related to “360 degrees” and the meaning is that the company covers all the angles of a specific industry, service, or product.

365 Response – 365response.org . The number here represents the 365 days of a year. The underline meaning is that the service is available every day.

Can You Use Hyphen in A Domain?

You can use a hyphen in a domain but not 2 consecutive hyphens in the third and fourth positions. For example, buy-company-name.com is acceptable but my–newcomputer.com is not a valid option.

Although hyphens are valid in a domain, it is strongly advised not to use them. People can easily type the version without the hyphens and you can lose traffic. If you decide to use it after all, just use one that connects 2 words.

I would like also to mention that a hyphen doesn’t affect your performance on search engines (Google, Yahoo, Bing). They evaluate websites based on content and other factors. A website with a hyphen can succeed if the content is good or there is a clever marketing approach.

Here are some examples of domains with hyphens.

Sci-fi – sci-fi.com

Luxury Hotels – luxury-hotels.com

Adspree Media – online-games.com

Black Jack – black-jack.com

Is Underscore Allowed In A Domain Name?

You can’t register a domain with an underscore. If you try to use underscores then your domain registrar will ignore them or you will get notified that the domain contains invalid characters.

I tried to use underscores in 2 different domain registrars and below you can see the results.

Can You Use An Ampersand In a Domain Name?

You can’t use an ampersand in a domain. Companies use “and” in their domains instead or they decide to skip it at all. In some cases, they use a hyphen instead.

Here are some examples for all the cases:

Bath & Body Works – bathandbodyworks.com

Jack Henry & Associates – jackhenry.com

Stop & Shop – stopandshop.com

Rag & Bone – rag-bone.com

Sullivan & Cromwell – sullcrom.com

Allen & Overy – allenovery.com

Are Domain Names Case Sensitive?

Domain names are not case sensitive. If you try to use capital letters they will just convert to lowercase letters. For example, Buycompanyname.com, BuyCompanyName.com, and BUYCOMPANYNAME.COM are exactly the same.

Try to type all the versions on your browser bar and you will see that they end up to the same site. Try also to register a domain with capital letters and you will find out that it will convert to lower case.

Can You Use Non-English Characters in A Domain?

You can use characters from many different languages in a domain like Chinese, Arabic, Greek, and others. These domains are called internationalized. In the background, these domains are actually translated to English characters and numbers so the domain name system can recognize them.

For example, if I register the German name müller my domain registrar will translate that to xn--mller-kva. You can use that conversion tool from Verisign with letters from your local language conversion tool.

There is a big portion of the human population that they don’t speak English but they use the web so there was a need for that addition.

You can’t mix different languages in a domain name. You should choose one language and stick with it.

**Previously I mentioned that you can’t use hyphens in the third or fourth position. You see now why this is happening. The hyphens in those positions indicate that the domain was registered as an internationalized one.

Why Do We See Dots in Domains Sometimes?

You might have seen some website addresses like that maps.google.com. You can’t actually register this kind of phrase with a dot “maps.google” but after you register your domain you can create subdomains.

For example, now that I own buycompanyname.com, I can create as many subdomains as I want like blog.buycompanyname.com, login.buycompanyname.com, pay4.buycompanyname.com, etc. You do not pay additional money for these options.

For example, google registered google.com and they have created many subdomains for different services. Pay extra attention that google paid for the other top-level domains such as google.co.uk, google.co.in, etc.