Subdomain or subdirectory? How Google treats each, and which to use

A subdirectory is a folder on your main domain (example.com/blog). A subdomain is a separate host name in front of it (blog.example.com). Google has said for years that it can rank either and does not inherently favor one. The practical difference is how clearly a section reads as part of your main site: a subdirectory is understood as the same site immediately, while a subdomain that looks like a separate site may be treated more like one. So content meant to build your main site's visibility, such as a blog, guides or location pages, usually belongs in a subdirectory, and genuinely separate systems like apps, stores on other platforms or help centers fit naturally on subdomains.

The difference in one table

How Google actually handles each

Subdirectories

A subdirectory is just a path on your domain. Google crawls it as part of the same site, it inherits your site-wide signals, and everything you publish there contributes to how Google understands your site's topics. Internal links from your home page and navigation flow into it naturally.

Subdomains

Technically, a subdomain is a different host. Google can and does understand that it belongs to the same organization, especially when the two are well linked and share branding. But a subdomain that runs on different software, uses a different design and is rarely linked from the main site can end up treated much like a separate website, building its own reputation more slowly.

One visible difference is documented by Google: site names in search results are supported for domains and subdomains, but not subdirectories. A subdomain like news.example.com can show its own site name; example.com/news shows the main site's name.

What Google does not do

Google does not apply a penalty or a bonus for either choice. The SEO case for subdirectories is about consolidation and clarity, not a rule. You will find case studies where moving a blog from a subdomain to a subdirectory lifted traffic; treat them as evidence that consolidation often helps, not as a guarantee.

When to use a subdirectory

Use a subdirectory for anything that should strengthen your main site in search:

• Blog and articles (/blog)
• Service and location pages (/services/roof-repair, /locations/naperville)
• Guides, glossaries and resources (/glossary, /guides)
• Landing pages for campaigns
• Language or country versions, where you want one site with hreflang (/es/, /en-ca/)

This is how we structure the sites we build, including this one: the blog, glossary, industries and the agency directory all live under one domain.

When a subdomain makes sense

Use a subdomain when the section is genuinely separate, usually because it runs on a different system:

• Web apps and customer portals (app.example.com, portal.example.com), which often should not be indexed anyway.
• Stores on a hosted platform (shop.example.com on Shopify) when your main site runs on something else. See DIY ecommerce: why you should probably use a platform.
• Help centers and documentation run by a support tool (help.example.com).
• Careers sites hosted by an applicant tracking system (jobs.example.com).
• Staging and test sites (staging.example.com), always blocked from indexing. See staging site.
• Separate brands or audiences that should build their own identity.

Can you put a separate platform in a subdirectory?

Often, yes. A reverse proxy lets example.com/blog serve content from a different system, for example a WordPress blog behind a Next.js marketing site, or a headless CMS feeding pages into your main front end. Netlify, Vercel and Cloudflare all support rewrites or proxies for this. It takes more setup and testing than a subdomain, so weigh it against how much the content matters for search. We explain the headless approach in what is a headless CMS.

Watch out for third-party content

Some sites rent out a subdirectory or subdomain to a partner, such as a coupon section or sponsored reviews, to borrow the main site's reputation. Google's site reputation abuse policy targets third-party content published to exploit a host site's ranking signals. Moving it to a subdomain does not make it acceptable. Only publish content you would stand behind as your own.

Moving between the two

If you are moving a blog from a subdomain into a subdirectory (or the reverse):

1. Map every old URL to its new address.
2. Set up 301 redirects for each page, not just a blanket redirect to the home page. See 301 redirect.
3. Update internal links, canonicals and your XML sitemap.
4. Verify both in Google Search Console and watch indexing for a few weeks. A Domain property, verified by DNS, covers all subdomains in one view.
5. Expect some short-term movement while Google processes the change.

Our guide to redesigning a website without losing SEO covers the full checklist.

Tracking and analytics

• Search Console: add a Domain property to see the main site and every subdomain together, plus URL-prefix properties if you want each section separately. For submitting sitemaps, see optimizing an AI-built site for search and AI.
• Google Analytics 4: one data stream can cover subdomains of the same domain; check that your cookie domain and referral exclusions are set so a visitor moving between them counts as one session.
• Consistency: keep branding, navigation and your business details the same across both. See why NAP+W consistency matters.

How we'd decide

• Content meant to rank and support your brand: subdirectory.
• A separate product, app, portal, store or tool on another platform: subdomain, unless a reverse proxy is practical and the content matters for search.
• A separate brand or audience: subdomain or separate domain.
• Anything not meant for search (staging, internal tools): subdomain, blocked from indexing.

Planning a site structure or a migration? Talk to us before you move anything, because redirects are much easier to plan than to repair.