Second-level domains and subdomains
How domain levels work: country second-level domains like .co.uk and .com.au, privately run second-level names like .us.com and .it.com, and how subdomains work.
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Not every domain you can register sits directly under a top-level domain. Some sit one level lower, and every domain can have subdomains. Here's how the levels work.
The levels of a domain
| Level | In shop.sunnybakery.co.uk |
|---|---|
| Top-level domain | .uk |
| Second level | .co |
| Third level (the registered name) | sunnybakery |
| Subdomain | shop |
Country second-level domains
Many countries organize names under second-level categories, like .co.uk and .org.uk in the UK, .com.au in Australia or .co.jp in Japan. Some countries, like the UK, also allow names directly under the main ending (.uk).
Privately run second-level names
Some companies own a regular domain and sell names under it, such as names ending in .us.com or .it.com. They look like extensions, but they're really subdomains of a privately owned domain. That means:
- The company that owns the parent domain controls the rules and prices.
- They're usually cheaper and more available.
- Resale demand is typically lower than for real top-level domains.
Subdomains
A subdomain is anything you add in front of your own domain, like www, shop, blog or help. You create them free in your DNS settings, and each can point to a different website or service.
- Use subdomains for separate apps or services, like app.yourbusiness.com.
- Use folders (yourbusiness.com/blog) for content you want to share your main site's search strength.
Questions
Is .co.uk a top-level domain?
No. .uk is the top-level domain and .co is a second level under it.
Are subdomains free?
Yes. You can create subdomains of your own domain for free in your DNS settings.