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Subdomains Vs Subdirectories: What Is Important For SEO in 2022?

Picture of Rebecca Gonzalez Rebecca Gonzalez : May 18, 2022

HubSpot B2B Marketing

One of the longest-running debates in SEO is the use of “subdomains or subdirectories" for website content such as blogs, landing pages, and resource libraries. Not to worry; we have got your answer right here.

What is a primary domain name vs. a subdomain?

A primary domain name for a website and a URL literally map the website name to an IP address where the website is hosted. For example, these are primary domains: orangemarketing.com, google.com, cnn.com, and so on. A subdomain means "a subdivision of a domain." A subdomain is a small word or phrase you see on the front of the primary domain. For example, when you migrate your blog to HubSpot, we will frequently recommend moving the blog to blog.orangemarketing.com. We like to use "go." or "info." as the subdomain for landing pages. Fun fact: even in the case of www.orangemarketing.com the "www" is a subdomain.

What's a Subdomain & How Is It Used? From HubSpot

Backstory: The history of the subdomain SEO debate

In the 2000s, when Google was less sophisticated, conventional SEO wisdom held that subdirectories (e.g. example.com/blog) were the way to go instead of subdomains (e.g. blog.example.com) and that your primary domain wouldn’t get any SEO credit for rankings earned by a subdomain. Meaning Google treated a subdomain 100% separately from a domain in website rankings. In 2011, Google substantially changed its search algorithm to acknowledge subdomains as part of domains, but the debate persists.

First look at how Google changed what subdomains mean for SEO, what exactly subdirectories and subdomains are, and what it means for your site if you want to move from one to the other.

Subdirectories

This website hierarchy has a root domain that uses subdirectories—also called subfolders—to organize your website content. Each subdirectory can build off of one another (almost indefinitely). This hierarchy can be great for SEO because it keeps any earned backlinks, domain authority, and page authority closely tied to the root domain. But beware: too many layers can create an SEO nightmare for both search engine spiders and your site visitors.

subdirectory structure

Subdomains

This type of website hierarchy is also under a root directory; however, instead of using folders to organize your website content, it's kind of like a website of its own. That's because it will usually have a separate content management system, templates, etc.—all while still being closely tied to the root directory or main domain. All subdomains are on the same level rather than being one within another, like with subdirectories. But each subdomain can have its own subdirectories if it makes sense for content organization.

When to use a subdomain

For smaller sites (less than 20 pages), a single-subdomain approach will be more than enough. More complex sites and any website with a content strategy will benefit from separating different types of content.

Subdomains can provide organization and structure to your site if you have a lot of different—but important—content to share. They're also ideal if your business houses content that would be difficult to manage on one website. And—according to HubSpot community consensus—the SEO pros of moving to a subdomain outweigh the possible (and mostly unknown and at this point theoretical) cons. In this day and age, we don't believe any cons exist. However, SEO know-it-alls and ancient web tech guys will die on the hill that subdomains hurt your website's ranking. Come on. Is Google actually that stupid? Nope. And we do not see evidence of any "hurt."

We frequently point the skeptics to this well-known 2017 video from Google Webmasters Trends Analyst John Mueller.

We like to follow HubSpot’s (you know that $1B company founded in 2006) approach and recommend the use of at least three subdomains - one for the main site, one for the blog, and one for landing pages. We sometimes add a 4th for a resources library. With proper use of the hub-and-spoke content model and judicious interlinking, all three will rank well for your site.

The takeaway

The bottom line is this: Google is smart enough to understand that blog.yourdomain.com is part of yourdomain.com. It will not hurt SEO and is not an immediate concern unless there are other issues such as duplicate content. poor metadata, bad URLs, and all the other SEO 101 items that should be top of your tidy-up list. Therefore, unless you’re already planning on reorganizing your website, there’s no SEO-specific reason for undertaking a project to remove subdomains and move entirely to a subfolder structure.