Subdomain vs Subdirectory:Which Should You Use?

A subdomain is a separate hostname under your domain, such as blog.example.com. A subdirectory (or subfolder) is a path on the same hostname, such as example.com/blog. Technically, a subdomain can point to a completely different server or service; a subdirectory is part of the same site. For SEO, Google says it can handle both, but keeping related content in a subdirectory makes it simpler to treat as one site.

The right choice depends on whether the content is part of your main site or a genuinely separate service.

The technical difference

	Subdomain	Subdirectory
Example	shop.example.com	example.com/shop
DNS	Needs its own DNS record	No DNS change
Server	Can be a different server or service	Same site and server (or routed through it)
SSL	Must be covered by the certificate (wildcard or separate)	Covered by the main certificate
Cookies and logins	Separate unless deliberately shared	Shared with the main site
Analytics	May need cross-domain setup	Works by default

When a subdirectory is usually better

• A blog, resources section or help articles that support the main site's topics.
• Product or service pages that belong to the main business.
• Language versions such as example.com/bn/, which are easy to manage with hreflang.
• Small sites where one CMS handles everything.

Keeping content in subdirectories means one site to maintain, one analytics setup, and internal links that clearly sit within one site.

When a subdomain is usually better

• A different application or platform: a helpdesk (support.example.com), a store on a hosted platform, a web app (app.example.com) or a status page.
• A separate audience or brand area that needs its own design and management.
• Technical isolation: different server, different security requirements, or a staging site (staging.example.com, kept out of search engines).
• Email-related services that need their own hostname.

What about SEO?

Google's public statements say it can crawl, index and rank both structures, and that you should choose what is easiest for you to maintain. In practice:

• A subdirectory automatically benefits from being clearly part of the main site.
• A subdomain may be treated more like a separate site in some respects, and needs its own Search Console property for full reporting.
• What matters most is content quality, internal linking and not splitting closely related content across several hostnames without reason.

If you move content between a subdomain and a subdirectory, use 301 redirects for every URL. See website redesign without losing SEO.

Setting each one up

Subdomain:

1. Create it in your hosting panel (cPanel → Domains) or point it at another service.
2. Add the DNS record: an A record to a server IP, or a CNAME to a service's hostname. See DNS record types explained.
3. Make sure SSL covers it.

Subdirectory:

1. Create the section in your CMS, or install an application into a folder.
2. If the content comes from another application, it can be served under a path with a reverse proxy, which is more complex and best done by someone experienced.

Decision examples

Content	Recommended	Reason
Company blog on the same CMS	example.com/blog	Same site, same tools, simplest to maintain
Help centre run on a separate helpdesk platform	help.example.com	Different platform, easiest to point by DNS
Customer web application with logins	app.example.com	Separate codebase, separate security boundary and cookies
Bangla and English versions of the same site	example.com/bn/ and example.com/en/	One site with clear language sections and hreflang
Staging or test copy	staging.example.com, blocked from indexing	Isolated from the live site
Online store on a hosted e-commerce platform	shop.example.com (or a full domain)	Platform-hosted, connected by DNS
Campaign landing page	example.com/offer	Benefits from the main site's reputation

Cookies, logins and security

Subdomains are useful security boundaries when used deliberately:

• a cookie set for app.example.com is not sent to blog.example.com unless it was set for the parent domain;
• separating an application from a marketing site means a vulnerability in a WordPress plugin on www does not directly expose the application's session cookies;
• but cookies set with Domain=example.com are shared with every subdomain, so set them narrowly.

See secure cookies explained.

Frequently Asked Questions

Is www a subdomain?

Yes. www.example.com is technically a subdomain of example.com. Choose one version as the main address and redirect the other.

Do subdomains cost extra?

No. Once you have registered the domain, you can create subdomains freely; you only pay for any hosting or services behind them.

Should my blog be on a subdomain?

Usually a subdirectory is simpler, unless the blog runs on a separate platform that cannot be served under your main domain's path.

Related reading

For DNS basics, read what is DNS and domain names explained. Register domains with the ServerNeed domain search.

Sources

• Google Search Central: URL structure best practices