Subdomain vs Subdirectory: What Strategy is Best in 2021? – In this article I am giving some practical advice on the subdomain vs subdirectory debate and choosing the right structure and hierarchy for your website.
Before we get to the nitty-gritty of the topic, it’s worth clarifying some of the terminology used in writing on subdomain vs subdirectory.
A domain (name) is the web equivalent of a physical address in the real world. A domain is used as a memorable name for a resource on the web, generally a website.
A domain name points to an IP address and has a minimum of two components: a Second Level Domain (SLD), which is the actual name of your website; and a Top Level Domain (TLD), which is the suffix attached to the SLD.
A domain name is an identification string that defines a realm of administrative autonomy, authority or control within the Internet (source: Wikipedia):
In general, a domain name identifies a network domain, or it represents an Internet Protocol (IP) resource, such as a personal computer used to access the Internet, a server computer hosting a website, or the web site itself or any other service communicated via the Internet.
The following are the types of domains commonly accepted:
A subdomain is the part of a domain that comes right before the main domain name. For example, in office.sherryfitz.ie ‘office’ is the subdomain of ‘sherryfitz.ie’.
A subdirectory is a subsection (for example, a folder or category) within the main domain name.
If you are thinking about your SEO strategy, choosing between subdomain vs subdirectory could play a significant role in the rankings and visibility for your pages.
For this reason, it’s important to choose wisely. Below I am listing a number of elements for you to consider.
The two main mentions by Google about subdomain vs subdirectory have come in the form of videos by respectively Matt Cutts and John Mueller. Let’s see what they say.
This is the first video posted by Google on the debate subdomain vs subdirectory.
Quoting from the video:
They [subdomains and subdirectories] are roughly equivalent
This is arguably the most quoted video when it comes to the debate subdomain vs subdirectory. It’s often used to reinforce the argument that Google makes no difference between subdomains and subdirectories.
Quoting from the video:
Google web search is fine with either subdomains or subdirectories
Before arguing what’s best for SEO, it’s worth taking a look at the differences between a subdomain vs subdirectory website structure.
Matt Cutts said that the two were roughly equivalent.
John Mueller said Google was fine with both but then he added three differences at the end of the video:
From the focus given to the word separately and per domain, you might have already guessed what I am going to write next: Google treats subdomains as separate entities from the main domain.
What does this mean?
The fact that Google treats subdomains as separate entities means two things when it comes to domain authority:
Links and content are considered by Google as two of its three main ranking factors, the third being RankBrain (source: semrush.com).
The domain authority for a website is a measure describing how successful (and valuable) a domain is in search results within a given topic area or industry.
There is a strong case arguing that switching from subdomains to subdirectories will increase the rankings, visibility and traffic for your website.
SEMrush mentions a few examples in this article about subdomain vs subdirectory:
I shared this on Twitter about 4 weeks ago, just wanted to re-share as it’s still going up… pic.twitter.com/KVKbdmnLfN
— Andy Chadwick (@digitalquokka) October 29, 2020
Not wanting to start an argument or anything, but here’s what happened when a retail client’s blog was moved from a blog. subdomain onto a /blog/ subfolder 📈 pic.twitter.com/LxMWBV2JAu
— Stephen Kenwright (@stekenwright) October 20, 2020
Both cases are relatively recent and show a significant increase in organic traffic following the moving from a subdomain structure to a subdirectory one.
We now know that if what we care is rankings, visibility and traffic, moving to subdirectories has its benefits.
Having said that, here are some cases where keeping a subdomain structure makes sense. Let’s take a look.
You might want to consider keeping your subdomain structure if you are happy with your overall organic traffic and your website falls under one or more of these use cases:
One common use case for subdomains is when you want to separate a specific department from the main domain.
For example, Google uses support.google.com to separate its support service from its main domain (and so does HP with support.hp.com).
The counter-argument for this example is that Google doesn’t really have to make a big effort to rank its pages on…Google.
If you have a multilingual website or a multi-regional one, it might make sense to keep the corresponding regions or languages as separate from the main domain.
The counter-argument here is that the same result is perfectly achievable through a subdirectory site structure, which brings the additional benefits of higher rankings.
Some companies want to keep their blog as separate from the main website. Hubspot with blog.hubspot.com is one of the main examples.
Again, Hubspot.com is not a website struggling with domain authority and its content marketing scope is so large that it could make sense to have a separate entity for the blog.
Many websites decide to have the ecommerce part of their business as a subdomain.
For the reason concerning domain authority and visibility, I am not particularly in favour of this choice and I would not recommend it for the average online store (especially brand new ones).
Microsoft with events.microsoft.com decided to separate its events section from the main domain. Again Microsoft doesn’t need to make an effort to rank its pages.
Before websites were responsive to screen sizes, it was common practice to create a mobile version of the website and upload it onto a subdomain, generally mob. or mobile.
Some companies like Facebook and Twitter still use this solution for those mobile users who access their website through a mobile web browser (and not through their mobile app).
The short answer is always use a subdirectory site structure unless your website falls under one of the use cases above.
Even then, make sure you evaluate the pros and cons of your choice:
Choosing the right site structure strategy could have a significant impact on your success online.
If you need an SEO consultation about this task, make sure you get in touch.