The Relationship Between SEO and Subdomains


SEO and Subdomains

Whether or not you should use subdomains to improve your site’s SEO has become a long-standing and hot topic debate across the internet. Their impact is debatable, especially when compared to the use of subdirectories.

If you are on the lookout for the best way to lay out your site’s architecture to maximize potential SEO results, then you will have some kind of voice or interest in this deliberation. What should you use? What is the best way to set up your website’s architecture?

Site architecture is a significant aspect of SEO and improving your rankings. Search engines can have trouble indexing and ranking you appropriately if it is too difficult to follow or disparate.

We take a look at the ins and outs of a domain, a subdomain, and a subdirectory, and how each of these impacts your SEO. Then, there is guidance for when to use a subdomain vs. a subfolder and the pros and cons of a subdomain, hopefully making it easier for you to select the option that suits your website the best.

Table of Contents

What is a Root Domain?

To better understand the nuances of a subdomain and a subdirectory, it helps understand what a domain is and its pieces.

Basically, a domain is the internet address of a website, the human-readable version. They have to be unique to every single website since they are its address, just like every home in every country has its own individual address.

A domain isn’t as simple as some might think, though. It is multiple parts and can experience multiple levels of personalization if you want.

Let’s work backward through a domain. We will use our site as an example:

Domain Name

Top-Level Domain (TLD)

The top-level domain, or TLD, is the last part of a basic domain name. On our website, the TLD is the “.com” at the end. However, there are quite a few TLDs available for use at the end of the domain name. Some of the more common ones include:

  • .com
  • .net
  • .org
  • .edu

These can also be made specifically for certain countries if the website primarily applies to visitors from that country. For example, if the website is British, it will often have a “” TLD, or if it is French, then it could end in “.fr” instead of a “.com” standard.

In these cases, the TLD can also be called a country code top-level domain or a ccTLD.

You can also choose from a wider number of TLDs. It doesn’t have to be configured to the standard. For example, if you have an agency site, you could end it with “.agency” or for an accountant firm, “.accountant.”

This isn’t standard since making a URL memorable and easily understood is essential for potential visitors and search engines. Doing this might confuse search engines, but it could confuse visitors looking for a standard ending to understand better and remember the URL.

Second-Level Domain (SLD)

SEO Domain Names

The next part of a domain name is called the second-level domain, or the SLD. This is commonly the central portion of a domain name. It is often the name of the company the website belongs to or a primary keyword of their site.

Using our website as an example, the SLD in is “firestarterseo,” our company name. It also functions as a primary keyword for the site and is memorable and sensible enough for potential clients to locate us on the internet.

Choosing your domain name is a big decision since it is a significant factor in search engine rankings. That being said, it is also one of many ranking factors and doesn’t determine your results more than most aspects. There are many sensible best practices to follow that limit your choices substantially when you choose yours.

That means you don’t have to find yourself paging through the dictionary anytime soon since the answer is normally wrapped up in your company name, logo, or description already.

If you ever see the term “root domain” while researching, know that a root domain is the combination of the Top-level and second-level domains that we have just covered.

What is a Subdomain?

Website Map

Since we are working backward piece by piece through a domain name, the next part is the subdomain. A subdomain is the “www.” at the front end of the entire domain. This piece is the article’s primary focus, how you can use it and adapt it for your specific site.

The confusion about subdomains often comes from an antiquated knowledge of how the internet works. In the early ’90s, when the world wide web was picking up traction, every website was required to place “www” at the beginning of their domain name.

In the modern age of the internet, this is still common practice but entirely unnecessary. Your subdomain can be anything you want it to be or doesn’t have to be there at all. This flexibility opens a lot of doors for some corporations and web designers. However, there is a significant debate about how much it can help in the end.

What used to be a good example of a large corporation taking advantage of subdomains was Google. They changed many of their subsidiary sites so that they begin with a subdomain, i.e., Now, though, they have reconsidered and changed it back to, structuring it as a subdirectory instead, which we will get into later in the article.

Currently, this serves as a better example of the rise and fall of their usefulness according to a search engine’s functioning. As algorithms and their scope of understanding changes, so does the use of a subdomain.

The Protocol

A quick note, at the very beginning of a domain, you have what is commonly referred to as a “protocol.” It will not always display in your URL bar since it isn’t technically part of the URL. You don’t have to type it to receive the same results if the rest of the domain name is there. It exists but functions happily in the background.

What is a Subdirectory?

Website Subdirectory

A subdirectory can also be called a subcategory or a subfolder, all of which are mutually common names.

Subdirectories give you a means of conveniently organizing your website’s URLs so that the site architecture makes sense and is simple to move through for a search engine crawler. Your website doesn’t only have one URL; instead, it should have an organizational pattern of URLs.

Using our website as an example again, is the primary domain name. To get from there to this article, you would click on our blog page, which would send you to That sends you to a page that allows you to search throughout the articles. In that case, “category” and “articles” are subdirectories or subfolders.

When you click on the link for this article, you go to a different subfolder made individually for each article. For this one, it is The entire block between the “/” is the subfolder, allowing you to use the primary keywords in the article’s title to better your rankings. If you haven’t already noticed, it is the “/” mark that denotes the arrival or end of another subcategory.

The way that you structure the subcategories is important and also changes for each site. You can follow best practices to set up your site, but that is not our focus today.

Pros of a Subdomain for SEO

There are plenty of ways that a subdomain functions as a positive part of your SEO strategy, although it can be risky to implement them and guarantee the positive results you want. Some of the advantages of subdomains include:

  • Search engines categorize subdomains as unique websites that are not related to the primary domain. They create more parent domains that can show up on search engine result pages. When that happens, it functions to further push your competition down the list of results and increase your chances of being found.
  • Being viewed as a separate category also gives you the benefit of enhancing your authority on a search engine, increasing your rankings since they enhance your stance of authority.
  • Subdomains allow you to target a specific set of new keywords separate from your primary domain. Doing so can enable you to target niche markets within your business’s broader spectrum or even extend to another country.
  • It describes the exact purpose of that part of your website (although, to reiterate, search engines will catalog them as separate websites.) For visitors, this can be helpful if they want to know that they have found the right web location.
  • If done properly, a subdomain can be indexed very quickly, benefiting from the main domain’s good “reputation.”

SEO Company

Cons of a Subdomain for SEO

Many of the positive aspects involved in using subdomains can also flip on you and cause issues. You need to handle them with skill to ensure they work the right way for you.

  • As a unique website that can create more competition for your adversary sites, it can also put you as competition against yourself. Instead of benefiting from the discoveries and search results on a primary site, these results will be split between the subdomains.
  • They require an SEO strategy independently from the strategy you had been using for your primary site.
  • When a new subdomain is established, it is akin to starting from square one. You will need to begin acquiring backpacks other than those that were acquired for your primary site.

Overall, the challenges of using a subdomain can be summed up by saying that your analytics will be entirely split between the site. It is exactly as though you had two websites running with somewhat of a similar focus.

When Should You Use a Subdomain?

There are times when it is appropriate to use a subdomain, and others when it doesn’t make enough sense. Sometimes, using subdomains can help boost your SEO, while at others, it can negatively impact it dramatically.

You should only use a subdomain when you are ready to invest plenty of time and effort into it, developing its own SEO strategy and setting it up apart from your primary site.

Examples of When to Use a Subdomain

To help clear this issue up for you and whether they can help your SEO, here are some examples of when to use a subdomain. These don’t cover everything, so if you are seriously considering implementing them, it can be worth getting professional advice.

  • When you want to rank for different keywords than you do with your primary domain.
  • To target a specific market, a niche inside of the market you primarily focus on.
  • For a site to reach a different location or serve another language beyond your primary website’s scope.
  • To better break up very large sections of a website. For example, many large corporations or companies have their support pages and forums under a subdomain such as From here, they break the support pages into subfolders.

There might be other times when it makes sense to use subdomains. If you are unsure, the best thing to do to avoid unnecessary risk with your analytics is to consult SEO experts.

Subdomains and SEO

When Should You Use a Subfolder?

A subfolder is a less risky option to take when you want to better organize your site as it continues to grow and develop. They keep all of your information, backlinks, and interactions in one place, under the same domain.

Examples of When to Use a Subfolder

There are certain times when it makes much more sense to use sets of subfolders than it does to place everything in separate domains. They are also more convenient to set up with much hassle. Examples of when you should use a subfolder include:

  • When you want all of your analytics and interactions to stay under the same domain.
  • If you want an effective and convenient way to set up your site’s overall structure to keep it crawlable and easy to categorize.
  • You are trying to establish and strengthen a website’s overall authority with high-quality content and well-developed pages.
  • Keywords relating to your niche market are all very similar and wouldn’t benefit from being separated, i.e., if you would only create competition for yourself by creating a subdomain for that set of keywords.

Subfolders, or subdirectories, are more commonly used than subdomains at this point. They will likely remain so. At least until search engines adapt to cataloging subdomains slightly differently than they do now.

Should You Use Subdomains?

The answer isn’t a cut-and-dry yes or no, unfortunately. Although it would make it easier if we could make a recommendation one way or another, there is rarely a black and white solution when it comes to questions relating to analytics and SEO choices. This dilemma only increases when you consider the fact that search engines are constantly getting tweaked, and their algorithms never stay the same for too long.

In Summary

The debate between using a subfolder versus using a subdomain and how these two entities can impact your SEO is ongoing.

Digital Marketing Experts

Hopefully, it is encouraging for you to realize that there are more than 200 factors that search engines commonly use to rank websites. Although some of these matters more than others, there is not a single one that on its own can make or break your ranking factor.

Domain names are only one out of these 200 total factors. The best thing to do is to have another read through the examples of when it makes sense to use a subdomain or a subfolder and try to plug yourself into one of those examples.

In the end, do what makes the most sense for you. If the war continues to rage between the two options in your mind, get help from a team of SEO experts like you’ll find at Firestarter that can make the right call for you.

You don’t need to stumble around in the dark. We can light a fire and show you the way.


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