Subdomain or subfolder for SEO?

Google can crawl and index both, and it has not said that one ranks better. A subfolder (example.com/blog/) keeps everything under one host and is the simpler choice for most sites. A subdomain (blog.example.com) suits a separate system, a different team or a different technology stack. Choose for practical reasons and then stay consistent.

Why it matters

A subdomain is a prefix to your domain, such as shop.example.com. A subfolder is a path on the same host, such as example.com/shop/. Search engines treat a subdomain as a separate host, which affects reporting, cookies, security settings and how you manage the site. Moving later means redirecting every address, so it pays to decide early.

How to decide

Ask whether the section runs on the same platform as the main site. If your blog is in the same CMS, a subfolder is natural and needs no extra DNS.
If the section is a separate application, such as a hosted help centre or online shop on another service, a subdomain may be the only option. Some services can run in a subfolder through a proxy, which takes more setup.
Think about who looks after it. Separate teams, separate releases and separate security needs can all favour a subdomain.
Think about reporting. In Google Search Console, a Domain property covers every subdomain, while a URL-prefix property covers only the exact address you enter. Analytics may also need extra setup to follow visitors across subdomains.
Think about shared files. Cookies, login sessions and security headers are easier to share within one host, and a subdomain needs deliberate configuration.
Check what each option requires from the DNS records and the HTTPS certificate:

blog.example.com.   CNAME   hosting.provider.net.

Whatever you choose, link the section clearly from the main navigation, include its URLs in a sitemap and give every page one canonical address.
For languages and regions, read the separate international guide, because the choice there involves hreflang as well.

Common mistakes

Moving a working blog between a subdomain and a subfolder for SEO reasons alone, without redirects for every URL.
Creating many subdomains with thin content.
Forgetting to add the subdomain to Search Console or to its own sitemap.
Splitting content that belongs together across hosts.
Leaving the old section reachable at both addresses.

Frequently asked questions

Does a subfolder pass more authority?

Google has not said so. Treat any claim about it with caution and decide on practical grounds.

Can I use both?

Yes, many sites do, for example a subfolder blog and a subdomain help centre. Keep each section consistent and well linked.

Which is easier to move later?

Neither is easy. A move changes URLs, so every old page needs a 301 redirect to its new address.

To check how your own site is set up, Try the free website sample.