What Is a Subdomain?
How a Subdomain Relates to Its Parent Domain
What is a subdomain? A subdomain is an extra label placed to the left of a registered domain, creating a separate address under the same parent. For example, shop.example.com is a subdomain of example.com. For how a domain fits into a full web address, see domain vs URL.
The owner of the parent domain controls its subdomains. They share the same registration, so no separate domain has to be bought. Each subdomain can point to a different server or service, which is why one domain can run a website, a blog and an email service at the same time.
Why Websites Use Subdomains
Subdomains are a common way to separate parts of an online presence that serve different purposes:
- shop. An online store that runs on its own platform.
- blog. A blog hosted separately from the main site.
- support. A help center or ticketing system.
- mail. A service used to send and access email.
- staging. A copy of the site used for testing before changes go live.
Subdomains also keep names clear. Each one tells the visitor what to expect before they click. The wider structure of a name is discussed in parts of a domain name.
Example: A Company With Three Services
A hardware company runs its main site at example.com, its online store at shop.example.com and its support portal at help.example.com. The store is built with one platform and the portal with another, so each is managed by a different team.
Customers see one brand and one registered domain. The company pays for one registration, and its teams can change their own systems without renaming the whole business.
Frequently asked questions
Is a Subdomain Cheaper Than a Separate Domain?
Usually. A subdomain does not need its own registration, because it sits under a domain the owner already holds. A separate domain has its own registration and renewal. The trade-off is that a subdomain is tied to the parent's name, so it cannot be sold or moved on its own. The basics of registration are in what a domain name is.
Is www a Subdomain?
Yes. www is the most common subdomain, but it is only a convention. The bare domain without www is a separate name, and both can be set up to show the same site. Using one version consistently helps visitors and keeps links tidy.