Subdomains vs. Subdirectories: What’s the Difference?

For a company’s content marketing strategy to truly be complete, a solid understanding of search engine optimization, or SEO, is critical.

Those familiar with digital marketing know on-page and off-page SEO and can explain the difference between the two. But businesses can also utilize SEO in places they might not expect. What we’ll explore here is a more granular aspect of SEO: subdomains and subdirectories.

What are they? What’s the difference between the two? How and when should you use a subdomain or a subdirectory? We’ll define these two terms, discuss the pros and cons of each, and help you decide which system works best for your business.

Subdomain vs. Subdirectory

When considering ways to enhance your SEO, you may not immediately think of changing your website organization or the look of your URL. But you have options, and the choice between them could bump you up in the results. Before delving into subdomains and subdirectories though, it’s crucial to understand domains and how they function.

How Do Domain Names Work?

In short, a domain name is the name of your website, pointing users to the location where they can access its information. Computers use the internet protocol (IP) address of an individual computer to find a website, but an IP address is a string of difficult-to-remember numbers. A domain name acts as a kind of shorthand, pointing users to the same place as an IP address while being easier for people to remember and use.

A domain name can be any combination of letters and numbers used with a suffix like .com. This suffix indicates which top-level domain that name belongs to. These components become the root domain that everything on a site branches from.

Subdomains and subdirectories—also called subfolders—have to do with the organization of pages under that top-level domain. They’re two different ways of equipping root domains with new features like a blog or a storefront page.

What Are Subdomains?

Put simply, a subdomain is a domain that is part of another primary domain.

Subdomains are often easier to set up for remotely hosted websites, as their servers can be scattered around in different locations. For many modern sites that use cloud hosting, a subdomain can be a faster approach to getting your site off the ground and connecting pages back to your principal domain.

An example of a subdomain URL might be support.callrail.com. This connects the subdomain of the blog page back to the main domain, callrail.com. It would be the same for community.callrail.com or any other page within the main www.callrail.com domain. Since they aren’t organized in subfolders, all that’s needed to connect them to a domain name server (DNS) is a single CNAME record.

What Are Subdirectories?

Subdirectories are an older way of organizing sites that some webpages still use by default. Also called subfolders, subdirectories organize sites and their pages into a directory of folders, like files on a computer. An example of a subdirectory URL is callrail.com/blog. Subdirectories host everything in the same place, as opposed to cloud servers that might be broken up, which can make maintaining the site easier.

Should I Use a Subdomain or Subdirectory for My Website?

The system you use for your site depends on you and your business. Generally, subdomains are ideal for larger businesses with multiple sizable entities, while subdirectories are a safe approach for small business owners who are new to digital marketing.

Subdomains, Subdirectories, and SEO

Do search engines favor one option over the other, though? According to Google’s Webmaster Trends Analyst John Mueller, not really. In an interview with Will Critchlow from Moz, Mueller said that SEO concerns shouldn’t affect your choice between subdomains and subdirectories: Google’s crawlers and algorithms don’t take the setup into account when ranking a page.

Google has been rather consistent in addressing this question, as many prominent Googlers have defended Mueller’s claim. Another Webmaster Trends Analyst, Gary Illyes, has also gone on the record at multiple events to reinforce the company’s official position on the subject.

That said, some site owners have reported that a simple change of subdomain to subfolder, or vice versa, can result in a traffic increase. Mueller says there could be situations where the search engine treats certain pages differently, even though it sees both setups as equal.

For example, is a page a part of a larger site or a site on its own? Sometimes, Google’s algorithm will see a subdomain as separate but treat a subdirectory page as part of a larger site and therefore rank it differently. But Mueller stresses that this isn’t a guarantee.

“In general, we see these the same,” he said during a Google Hangout session on the subject. “I would personally try to keep things together as much as possible. So, if it’s the same site then try to put them on the same site, essentially, and use subdomains where things are really kind of slightly different.”

In other words, the best structure for your site will depend on the structure of your business or businesses. Google’s Public Search Liaison Danny Sullivan may have put Google’s perspective on the matter into clearest terms when he followed up on Mueller’s take: “What’s better for SEO is generally doing what’s best for your users and yourself.”

When Is a Subdirectory the Best Option?

Subdirectories are usually the default for a reason: a subdirectory setup is easier to work with, at least in the early days of your digital marketing strategy. It requires less long-term effort to maintain and is therefore more accessible for small businesses.

And while Google’s official stance is that it treats both subdomains and subdirectories the same, it has also admitted that there are instances where search results will reward subdirectories.

Switching from a subdomain to a subdirectory setup may increase a site’s ranking. That’s because Google usually sees all the different pages of a subdirectory site as part of a whole.

Google treats each page of a subdomain-organized site, on the other hand, as a separate entity, and it can suffer from backlink dilution for this reason. If a site makes a list of the ten best companies in your industry and backlinks to a blog post on your website at blog.mysite.com, that attribution would only increase the authority of your blog page and not your site as a whole. Your blog page is considered distinct from—and equal to—its root domain, mysite.com.

Consolidating relevant domains with a subdirectory setup also consolidates the backlink profile of your site. Since pages aren’t seen as independent entities, each one adds authority to the whole website—potentially boosting your rankings.

When Is a Subdomain the Best Option?

If your business is on the larger side, and you have the time and staff to maintain several different properties, then you might want to opt for a subdomain approach. Subdomains are perfect for domains weighed down by files, like downloadable resources or blogs, or for hosting variants of your site. They can even be easier to implement from an operations standpoint, especially if you’re serving different applications or platforms like:

  • Community forums
  • Application status report
  • Helpdesks
  • WordPress or Movable Type websites

Subdomains are preferable if a brand has several large, distinct entities that need their own websites. Disney, for example, uses subdomains for its parks, video, and media properties to maintain them as separate entities. It markets each separately, directing external links back to their respective subdomains instead of a single domain containing content about every entity.

If your brand is organized around topics big enough to warrant their own domains, these entities are probably strong enough to stand on their own individual backlink profile. Combining such domains into a subdirectory setup would likely only sacrifice link equity due to changing every URL.

Prominent, robust interlinking between your subdomains is essential to keeping them toward the top of search results. The links should also be relevant, so as not to annoy the user—cramming a page full of unnecessary keywords or anchor text can actually penalize you in Google’s ranking.

How to Set Up Subdomains and Subdirectories

Setting Up a Subdirectory

Most basic websites are already organized using subdirectories by default. The server organizes the pages like files in a file system: home.com, home.com/blog, home.com/gallery, and so on. The creation process for a new subdirectory is pretty simple:

  1. When installing a new website using WordPress or another similar application, you’ll first select a location for the subdirectory. You should be able to do this with relative ease using the application’s dropdown menu.
  2. Once a location for the new subdirectory has been selected, review the name you’ve selected. Make sure it’s unique and doesn’t conflict with any of the site’s other pages. If two pages in your site’s folder are named mysite.com/blog, you’ll get error messages, and the pages won’t work. If possible, try to avoid using anything other than alphanumeric characters. Stay away from dashes and hyphens, for example.

Setting Up a Subdomain

Subdomain setup starts in much the same way—you’ll have to choose a name for it first. To create a new subdomain for your website:

  1. Log into your website hosting dashboard.
  2. You should see the option to add a new subdomain in whatever web hosting interface you’re using. Once you choose its name, the URL should automatically generate using the root domain.
  3. If you’re working with cPanel, you’ll need to add the DNS record to the subdomain, which can be done through the web hosting menu from the main dashboard.
  4. Once the DNS record is added to the new subdomain, it’ll be ready to use once it has resolved, which can take up to a day.

Though setting up a subdirectory may be the simpler option, neither process will give you much of a headache. Most website hosting platforms ensure that creating either a new subdomain or subdirectory is easy to do.

Should You Change Your URL?

If you run a very large site using subdirectories, you may need to decide whether to switch to subdomains for different areas of your site. Obviously, this means making a URL change. Google’s Mueller has advised site owners on several occasions to “keep the same URL for the long run” so as to avoid the time it takes for Google’s algorithms to reprocess everything after the change.

If you decide to convert, do so with the understanding that your link equity will be reduced: Your historical link value will filter through redirection, which “leaks” some value. Redirection is necessary to maintain value, but these leaks are inevitable. With a large and complex site, redirecting mistakes are bound to happen—and overlooking the minutest of details could spell disaster for your organic search traffic.

In general, it’s best to stick with your domain and URLs for the life of your business, and that means choosing a good URL structure that will stand the test of time. Durable URLs address the problem of pages that might need to be updated over time without changing their URL and confusing the system. Best practices for creating durable URLs include:

  • Leave out things like names, dates, adjectives, and opinions
  • Focus on evergreen language
  • Ensure URLs match the core of the expected search keywords for that subject
  • Make URLs short, readable, and clutter-free

If you must change your URL, you’d better have a really good reason—and when you do change it, make sure you won’t have to keep doing so in the future.

Key Takeaways

To recap, your business should use subdomains if:

  • You have a bunch of large properties, distinct applications, or multiple website platforms
  • One domain has something different to offer than the rest of the site
  • You have the resources to maintain large sites that can stand on their own subdomain

Subdirectories are a better idea when:

  • You want to make sure all link equity is consolidated on one domain
  • Your business lacks the bandwidth to maintain and optimize the site
  • You don’t mind using one or the other, as subdirectories are easier to maintain

Consider these factors carefully when working website organization into your overall SEO strategy. Take into account the amount of time and energy you can dedicate to maintaining the site and what the site will be used for.

Of course, website organization should only be one part of your content strategy, so make sure you cover all of your bases for better SEO performance.