Subdomains vs Subdirectories: Which is better for SEO?

Subdomain or subdirectory for SEO? It is an age-old debate that still lives on today across the SEO community. We often hear people ask, how are subdomains and subdirectories different? How do they affect SEO? When should you use a subdomain vs. a subdirectory? While they still pose some debate among SEO professionals, subdomains and subdirectories can be very confusing topics for many.

Our experts at Blue Compass are here to help you understand the differences between subdomains and subdirectories, and more importantly, we're hoping to make it easier for you to decide which is the better option for your business. To make the best choice for your content, you must understand how Google treats subdomains vs. subdirectories from an SEO perspective and how your users interact with your content.

What is the difference between a subdomain and a subdirectory?

The primary difference between a subdomain and subdirectory is how they organize content on your website. The URL structure of your website is an important component for SEO and choosing between the two is a decision that should be made with a lot of thought and consideration. Let’s dive a little deeper into what exactly a subdomain and subdirectory are.

What is a subdomain?

A subdomain is an extension of your primary, or root, domain. It is a website separate from your primary domain meant to house a section or sections of your business. If you choose to split up websites by subdomain, you may have one or multiple. A subdomain will be placed at the front of the URL and look something like the example below:


What is a subdirectory?

On the other hand, subdirectories, or subfolders, are separate sections on a single website that you use to nest related pages – much like how files on your desktop work. For example, if you have services in your main navigation, this is the subdirectory that nests the individual services below it. Subdirectories come after the slash of a primary domain in your URL and look like this:


Do search engines treat subdomains and subfolders the same?

Choosing a subdomain or a subdirectory will not affect Google’s capabilities for crawling your site, but will affect how Google views the structure of your site, because they treat subdomains as if they're a separate website. In the world of SEO, many professionals believe this can hinder organic traffic and overall rankings because you are splitting up your content and SEO value between more than one website.

Unlike subdomains, Google treats subdirectories as a single entity, no matter how many subdirectories you have, because they still live on your primary domain. Structuring your site with subdirectories will consolidate all SEO signals into one domain giving it all of the SEO potential that comes from backlinks, content and more.

So, do subdomains affect SEO?

Subdomains themselves are not bad for SEO. They do not cause any ranking penalties and are indexed like normal. But how you use them can impact the SEO and SEO potential of your website.

To start, picking a subdomain vs. a subfolder will fragment SEO signals and value across multiple websites. This does not mean that a subdomain can’t be valuable. There are many scenarios where a subdomain might be right for your business. But, before deciding, let’s find out how to utilize subdomains properly to prevent negative results and get the most out of them.

Common Subdomain Mistakes

Common mistakes we see include having blogs and eCommerce live on a subdomain. These portions of a website tend to have high SEO value, including strong link structure, visibility in organic search, etc. If you use a subdomain for this type of content, you are fragmenting valuable content which receives quality traffic and therefore limiting the SEO potential of each subdomain.

Additionally, hosting content on a subdomain similar to the content on your primary domain is still flagged by Google as duplicate content. Duplicate content can tarnish your brand’s credibility and validity.

When would you use a subdomain? Examples of Subdomain Usage

Because of the increased SEO strength associated with keeping content together on a subdirectory, this is typically the better option when possible. However, there are scenarios where subdomains might make more sense for your site structure, or you simply can’t avoid them.

  • International Sites: Subdomains are often used for websites which have various versions of your website for different regions of the world. If you have a website in multiple languages, it may be easier to manage by choosing a subdomain vs. a subfolder. As an example, let’s assume you do have an English version of your website and a French version structured as a subdomain. The URLs would look something like: (English) and (French).
  • Subject Matter: Subdomains might be used when the content or subject varies from your primary domain. If a large corporation owns multiple brands or has multiple business units, it might make sense to separate them into subdomains to help search engines and users better understand how your business is structured. For example, if you own multiple brands and want to keep them under the same umbrella, but utilize different subdomains to separate them they would look something like:, and
  • Technical Considerations: Sometimes there are technical considerations which make it very difficult to host content in a subfolder, for example, if it’s hosted by a third-party vendor or on a different platform. The examples below are a few more common scenarios where it might be difficult to incorporate subdirectories:
    • E-commerce site using a different platform than your main website
    • Donation pages relying on a third-party tool
    • Online restaurant ordering through another service
    • Login to a customer platform
    • Tech support using a third-party knowledge base

    Which is better: subdomain or subfolder?

    If the content is related to the main website and you are able, it is best to host it on a subfolder. If you are not able to use a subdirectory, because of the technical considerations above, be strategic. You might consider various platform options (choose the most SEO-friendly platform), weigh the SEO pros and cons against the cost of an alternative method or tool, and think long-term to ensure a clear approach to incorporating future content into the website.

    Subdomains and SEO: How We Can Help?

    Deciding between a subdomain or subdirectory for SEO depends on a variety of technical SEO and user experience factors. Taking the time to consider how each can impact your site will pay off tremendously in the long run. There are so many things you can do to make your website more valuable, and doing so will build credibility, increase ranking and drive more traffic to your website. If you ever need help with your website or with search engine optimizations, we have a talented team of SEO experts here who are happy to assist with questions. Reach out to our team of digital experts at Blue Compass to see how we can help.

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    Kevin McMurray

    Kevin McMurray is a Digital Marketing Specialist at Blue Compass. He enjoys spending time with his family, cheering on Cyclones sports and leisure sports.