Subdomains vs. Subdirectories—What’s Best for SEO?

May 19, 2025

When organizing a website, one big question often comes up: “Should I use subdomains or subdirectories?”

At first glance, it may seem like a technical detail—but many businesses worry it could affect their SEO. The good news? Google says both are fine.

In the SEO Starter Guide, Google explains that your choice between subdomains and subdirectories does not directly impact rankings. Instead, you should pick the option that works best for your team, your site’s structure, and your long-term goals.

Let’s break it down.

What’s the Difference?

🔹 Subdomains

A subdomain appears before your main domain name.
Example: blog.yourwebsite.com

This is often treated like a separate site with its own structure and sometimes even its own CMS or hosting.

🔹 Subdirectories

A subdirectory appears after the domain name.
Example: yourwebsite.com/blog

This keeps all content under the main domain, organized like folders on your site.

What Google Really Says

According to Google:

“From a business point of view, do whatever makes sense for your business.”

Subdomains and subdirectories are treated equally in terms of ranking. What matters more is how you manage and structure the content inside them.

In short: if your blog is on a subdomain or a subdirectory, it won’t make or break your SEO—as long as the content is strong.

This is just like how your TLD (.com, .org, etc.) doesn’t impact SEO either. Google is focused on what’s on the page, not what’s in the URL structure.

So... Which One Should You Use?

Here’s a quick way to decide:

Use a Subdirectory if:

You want to keep all your content under one site for easier tracking
Your content is closely related to your main business
You want to share SEO value across all sections of your site

Use a Subdomain if:

You’re separating very different types of content (like support vs. marketing)
Different teams manage different areas of the site
You need more flexibility with design, CMS, or hosting

Many large businesses use subdomains for blogs, help centers, or apps. That doesn’t hurt SEO—it’s just a matter of what works for the structure and team.

Will Subdomains Split SEO Authority?

In the past, people worried that using a subdomain would “split” SEO power from the main site. That’s less of a concern today.

Google’s crawlers can understand the connection between your subdomain and main domain—as long as you link them properly and keep the content relevant.

What you want to avoid is creating disconnected websites that aren’t easy to navigate. Strong internal linking helps unify everything, whether it’s in a subdomain or a subdirectory.

(Need help organizing links? Our SEO 101 guide explains how structure plays a big role in site visibility.)

Examples in the Real World

HubSpot uses a subdomain for its blog: blog.hubspot.com
Moz keeps everything under a subdirectory: moz.com/blog

Both sites rank well. Why? Because they focus on great content, clear structure, and user experience—not URL format.

Final Thoughts: Focus on Structure, Not Format

Google doesn’t care whether you use a subdomain or a subdirectory. What it does care about is:

Clear navigation
Useful, relevant content
Mobile-friendly pages
Fast loading speeds

So pick the structure that makes the most sense for your business. Whether it’s yourwebsite.com/blog or blog.yourwebsite.com, your SEO success depends on the content—not the folder it lives in.