A subdomain is a subset of your main domain name that helps organize or separate different parts of your website. It’s placed before the root domain, like blog.example.com or shop.example.com. This structure allows you to run multiple websites or sections under one main domain while giving each a distinct URL.

Subdomains are commonly used to create separate areas of a site such as blogs, e-commerce sections, customer portals, or localized versions. They're often helpful for businesses that want to keep their content organized or cater to different audiences without purchasing multiple domain names.

For example, a business might use store.yourcompany.com to run an online shop while keeping their primary site at www.yourcompany.com. It’s a clean way to manage content and enhance navigation while keeping your website cohesive.

Why use a subdomain?

Using a subdomain gives you flexibility in how you structure and manage your content. You can develop it separately from your main site, apply a different design or CMS, and even host it on a different server. This is especially useful if you're creating different user experiences like a support center or an online store.

Plus, subdomains can help with testing new features, launching campaigns, or serving content in multiple languages—without disrupting your main site.

How subdomains affect SEO

Subdomains are treated by search engines as separate entities from your main domain. This means they require their own SEO efforts. If you're adding a blog or an online store, consider whether the SEO benefits are stronger under a subdomain or a subdirectory (example.com/blog) depending on your goals.

That said, subdomains can still rank well if optimized properly. They're just not guaranteed to inherit the main domain’s authority automatically.

Subdomain vs. subdirectory

Here’s a quick breakdown of the difference:

• Subdomain: blog.example.com
• Subdirectory: example.com/blog

Subdirectories are part of the same site structure, which means they typically benefit from the main domain's SEO value. Subdomains are more independent, making them ideal for distinct teams, content types, or tech stacks.

When to use a subdomain

Subdomains make the most sense when you want to:

• Host a blog or learning portal
• Create a separate e-commerce experience
• Run a member login or customer dashboard
• Test or develop features before launching
• Support localized or language-specific content

With a reliable AI website builder like B12, it’s easy to manage both your main site and your subdomains for a seamless user experience.

FAQs about subdomain

What’s the difference between a subdomain and a domain?

A domain is the primary address of a website, like example.com. A subdomain is an extension of that, such as blog.example.com, used to separate or organize content.

Can I have multiple subdomains on one website?

Yes, you can create as many subdomains as you like under one domain. They’re useful for managing different parts of your business or website content.

Do subdomains cost extra?

Typically, no. Most domain providers allow unlimited subdomains once you own the main domain. However, managing each may require additional resources or hosting setup.

Do I need technical skills to set up a subdomain?

Some hosting platforms require manual setup, but many website builders, like B12, make it easy with built-in tools and support.

Will a subdomain affect my site’s performance?

Only if it's hosted inefficiently. A well-built subdomain shouldn’t negatively impact your main site’s speed or performance.

Why subdomains matter in building flexible online experiences

A subdomain gives your business the freedom to grow, test, and organize digital experiences while keeping everything connected under one brand. Whether you’re building a new blog, launching an e-commerce site, or setting up a client portal, subdomains offer a scalable solution. And with tools like B12 and its built-in support for features like client engagement, email marketing, and online scheduling, you're equipped to deliver standout experiences across all sections of your site.

Looking to build or expand your website with subdomains? Get started today with B12’s easy-to-use AI tools.