How to distinguish between subdomains and subdirectories? Explain the impact on SEO

If you want to add a new topic to your website that hasn’t existed before, you have two options: Add Subdomain or Add Subdirectory .

What are the differences between the two, and how should I use them in terms of SEO?

In this article, we will introduce the difference between subdomains and subdirectories and their impact on SEO.

In addition, we also interviewed Mr. Shigeki Matsuo, CEO of Webrider Co., Ltd., who operates an SEO consulting business in Japan and has a track record in various industries. We have explained how it should be used.

Table of Contents

A subdomain is a division of one domain and is used when updating content in a category different from the main domain.

Subdirectories, on the other hand, form a hierarchical structure within a single domain.

A subdomain is the part of the URL that immediately precedes the domain name . For example, in the URL “blog.hubspot.com”, “blog” is the subdomain. 

• Main site: hubspot.com
• Subdomain: blog.hubspot.com

A subdomain functions as a single domain, and ‘hubspot.com’ and ‘blog.hubspot.com’ are independent websites.

Subdirectories, on the other hand, are tied behind the domain. For example, if you have a blog category on ‘hubspot.com’ and the URL for that category page is ‘hubspot.com/blog’, the ‘blog’ part will be a subdirectory.

• Main site: hubspot.com
• Subdomain: blog.hubspot.com
• Subdirectory: hubspot.com/blog

Subdirectories are found on most websites, such as “hubspot.com/blog” and “hubspot.com/about” to create a hierarchy within a single website.

Subdirectories may be relatively easy to imagine, but it may be difficult to imagine how subdomains are used. Below are some common use cases.

1. Support

Sometimes it’s better to separate the main site from customer support.

For example, Google uses support.google.com instead of google.com/support. This is probably due to the structure of the site.

Google.com is primarily a search engine. Google’s support department is not part of the search business. To properly connect with your users and provide support, you should have a dedicated subdomain.

2. Region

When providing services to multiple regions both in Japan and overseas, it is a point to hesitate whether to operate with a subdomain or a subdirectory.

Google explains that either method works, but each method has different advantages and disadvantages. Refer to the following Google page and choose the method that suits your company.

However, as described at the beginning of this page, when operating a site in multiple languages, it is also important to use hreflang annotations to convey the language of the site (web page) to Google.

3. Blog

Many companies operate their blogs on subdomains. HubSpot is no exception.

The URL of the English version of the blog on which the page you are viewing is based is blog.hubspot.com . Technically speaking, the English version of this article is located in the Marketing subdirectory of the blog.hubspot.com subdomain (https://blog.hubspot.com/marketing/).

If you have a lot of content, you may want to run your blog on a subdomain. It’s also a good idea to make your blog a subdomain if you want to build your expertise in a niche.

4. E-commerce store

Placing your e-commerce store on a subdomain can be beneficial if you have something you want to sell other than your usual products or services.

HubSpot’s e-commerce store also uses this method, and has shop.hubspot.com where you can purchase apparel, mugs, ballpoint pens, backpacks and other original products separate from the main software .

5. Events

If your company hosts regular or irregularly recurring events and you have a dedicated event category for your content, it’s a good idea to separate them into subdomains.

Again, subdomains are useful if you want to separate some sections of your site from your regular product or service section.

For example, Microsoft created a subdomain, events.microsoft.com , to separate event-related content.

Now let’s take a closer look at how subdomains and subdirectories affect SEO.

In the video below (in English), Google Webmaster Trends Analyst John Mueller says, “There is no better or worse between subdomains and subdirectories in the Google search engine. Neither is better for SEO, so use them according to your purpose. It should be fine, ” he explains.

Subdomains are considered separate from the main domain, so even if the core website content has already established authority, it cannot be inherited by subdomains .

On the other hand, subdomains are often used by large companies because they can be operated as independent businesses in different fields . For example, Disney uses subdomains such as shop.disney.com and movies.disney.com .

Subdomains have the advantage of helping you build authority in your niche . For example, you may want blogs to be recognized as a separate category from products and services.

Conversely, if you have a single category of content, you don’t necessarily need to use a subdomain . Basically, it’s easier to collect backlinks if you consolidate to one website. If you don’t really have a reason to use a subdomain, use a subdirectory.

On the other hand, Mr. Matsuo, CEO of Webrider, expressed the view that the effect of using subdomains or subdirectories for SEO purposes is disappearing .

[Profile of Shigeki Matsuo]

After graduating from the Faculty of Economics, Kwansei Gakuin University, he worked for a music production company and was involved in the production of stage music. After that, she became independent as a freelancer in 2005 and established Webrider Co., Ltd. in Kyoto in 2010. He is engaged in web marketing consulting and content production centered on attracting search customers.

Main content produced so far is “Silence Web Marketing” “Silence Web Writing”, and media includes “Delicious Wine”, “Delicious Izakaya”, “Betters”, and “CHECK-LIST”. The silence series was made into a book and became a bestseller with over 100,000 copies sold. In the fall of 2017, he produced the writing advice tool “Bunken”.

As a piano player and composer, he provides music for events such as “National Cultural Festival Kyoto” and Kifune Shrine in Kyoto.

“In the past, when searching for a certain keyword, both the main domain and subdomain pages were sometimes displayed. However, as search engine algorithms have been updated, this kind of thing has almost disappeared.” (Matsuo)

Based on this situation, Mr. Matsuo is cautious about using subdomains and subdirectories for SEO purposes.

“As mentioned earlier, it is no longer a good idea to use subdomains to increase the number of entrances from search results. There is even a risk that you will lose it.

However, subdomains look better than subdirectories when you want to separate themes on your site. There is absolutely no problem with using subdomains for that purpose, and rather it can be said to be an ideal UX.

Also, when creating content within a domain, there is also the idea that a subdirectory is easier to inherit the reputation of the root domain than a subdomain. This has to do with subdirectories being explicitly child elements of the domain. However, I personally think that the difference in evaluation between subdomains and subdirectories will gradually become smaller.” (Mr. Matsuo)

It’s a confusing topic, but ultimately it’s up to the website operator’s needs which one to choose .

Subdomains are a great way to clean up a complex hierarchical structure of your site. If you don’t have to, use subdirectories so that your main domain gets the most benefit from backlinks.