A subdomain is a prefix added to your main domain that creates a separate section or site at its own address — for example, blog.yoursite.com or shop.yoursite.com, where ‘blog’ and ‘shop’ are subdomains of yoursite.com. Subdomains let you organise different parts of your site, or run separate sites, under one domain, all for free (they do not cost extra like a new domain would). They are useful for things like a blog, a store, a support section, or a staging site, and you create them easily in your hosting control panel. Understanding subdomains helps you structure your web presence flexibly.
This guide explains what a subdomain is, how it differs from a subdirectory, common uses, and how to create one.
Did you know?
Subdomains are free and unlimited on most hosting: because they are just prefixes on a domain you already own, you can create as many as you like without registering new domains.
What a subdomain is
A subdomain is a part added before your main domain name, separated by a dot, that acts as its own distinct web address. If your domain is yoursite.com, then blog.yoursite.com, shop.yoursite.com, and support.yoursite.com are all subdomains — each a separate address under the same main domain.
Technically, a subdomain lets you host separate content or even a separate website at that address, while still being part of your main domain. It is a way of creating divisions within your domain without needing to buy additional domains, since subdomains are free extensions of a domain you already own.
Subdomain vs subdirectory
It helps to compare a subdomain with a subdirectory (a folder), since both organise your site. A subdomain sits before the domain (blog.yoursite.com), while a subdirectory sits after it as a path (yoursite.com/blog). Both can hold a blog, but they are structured differently.
The practical difference: a subdomain is often treated as a more separate entity — useful for distinct sections, separate applications, or content you want somewhat independent — while a subdirectory keeps everything as part of one site under the main address. For SEO and structure, a subdirectory keeps authority consolidated under the main domain, whereas a subdomain is more separated; which to use depends on whether you want the section closely integrated or more independent.
Common uses for subdomains
Subdomains are handy for organising or separating parts of your web presence. Common uses include:
- A blog: blog.yoursite.com, kept somewhat separate from the main site.
- A store: shop.yoursite.com for an ecommerce section.
- A support or help centre: support.yoursite.com or help.yoursite.com.
- A staging site: staging.yoursite.com for testing changes.
- A separate app or tool: app.yoursite.com for a web application.
- Region or language versions: uk.yoursite.com, for example.
Pro Tip
Subdomains are great for things you want somewhat separate from your main site — a store, an app, a staging area. For content you want fully integrated for SEO, like a blog you want boosting your main domain, a subdirectory (yoursite.com/blog) is often the better choice.
Why subdomains are useful
Subdomains are useful because they let you structure your web presence flexibly, at no extra cost. You can run distinct sections or even entirely separate sites — each with its own address, and potentially its own design or software — all under the one domain you already own, without buying more domains.
This flexibility is valuable for growing or multifaceted sites: you can add a store, a blog, a support centre, or a test site as a subdomain whenever you need one. And because subdomains are free and usually unlimited on hosting, you can organise things exactly as you like. They are a simple, powerful tool for shaping how your site is structured.
How to create a subdomain
Creating a subdomain is easy and done in your hosting control panel. There is typically a ‘Subdomains’ section where you enter the prefix you want (like ‘blog’ or ‘shop’), choose the main domain, and create it. The host sets it up, usually pointing it to a folder on your hosting where that subdomain’s content lives.
Once created, the subdomain works as its own address, and you can install software (like a separate WordPress) or place content there as you would for a main site. So adding a subdomain is a quick, free way to expand your site’s structure — a few clicks in your control panel gives you a new section or site under your domain, ready to build.
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FAQs
What is a subdomain?
A subdomain is a prefix added to your main domain that creates a separate section or site at its own address — like blog.yoursite.com or shop.yoursite.com, where ‘blog’ and ‘shop’ are subdomains of yoursite.com. Subdomains organise parts of your site, or run separate sites, under one domain, for free.
What is the difference between a subdomain and a subdirectory?
A subdomain sits before the domain (blog.yoursite.com), while a subdirectory sits after it as a path (yoursite.com/blog). A subdomain is treated as a more separate entity, good for distinct sections or apps; a subdirectory keeps content part of one site, better for SEO consolidation under the main domain.
What are subdomains used for?
Common uses include a blog (blog.yoursite.com), a store (shop.yoursite.com), a support centre (support.yoursite.com), a staging site (staging.yoursite.com), a separate app (app.yoursite.com), or region and language versions. They organise or separate parts of your web presence under one domain.
Do subdomains cost extra?
No. Subdomains are free extensions of a domain you already own, so they do not cost extra like registering a new domain would. Most hosting lets you create subdomains for free and usually without a strict limit, so you can organise your site however you like at no additional cost.
Should I use a subdomain or subdirectory for my blog?
For a blog you want to boost your main domain’s SEO, a subdirectory (yoursite.com/blog) is often better, as it keeps authority consolidated under the main domain. A subdomain (blog.yoursite.com) suits content you want somewhat separate. Choose based on how integrated or independent you want the blog.
How do I create a subdomain?
In your hosting control panel, there is usually a ‘Subdomains’ section: enter the prefix you want (like ‘blog’), choose your main domain, and create it. The host sets it up, pointing it to a folder on your hosting. You can then install software or add content there as its own address.
The bottom line
A subdomain is a prefix on your main domain that creates a separate address — like blog.yoursite.com or shop.yoursite.com — letting you organise sections or run separate sites under one domain, for free. It differs from a subdirectory (yoursite.com/blog): a subdomain is more separate, good for distinct sections or apps, while a subdirectory keeps content integrated under the main domain, better for SEO.
Subdomains are useful for blogs, stores, support centres, staging sites, apps, and region versions, and because they are free and usually unlimited, they give you flexible control over your site’s structure. Creating one is a quick task in your hosting control panel. Understand subdomains and you can shape your web presence exactly as you like, expanding it whenever you need without buying more domains.
When you are ready, you can start with Hostinger and use code PROTIPS for the reader discount. A subdomain (like blog.yoursite.com) creates a separate section under your domain, for free — created in your control panel.