Subdomain vs subfolder: Everything you need to know

Understanding the impact on SEO of a subdomain vs subfolder

Search engine optimisation (SEO) experts have long debated about the use of a subdomain vs subfolder for improving a website’s SEO. 

What is a subdomain?

A subdomain is a part of the main domain of a website. It’s used to help organise a website into different sections and indicate where in the website’s domains you have navigated to.

When you look at a URL, you’ll find the subdomain to the left of the main domain:

What is a subfolder?

The subfolder refers to the sub-menu items that are also displayed in a URL. A subfolder can be found on the other side of the main domain:

Are subdomains or subfolders better for SEO?

We wish it were as simple as just writing “yes” or “no”, but the truth is there is disagreement in the SEO community about whether a subdomain or subfolder is better.

If you want the answer ‘straight from the horse’s mouth’ (and in this instance by horse we mean Google), the answer is that both are just as good as the other.

Matt Cutts, a former employee of Google, said in an online video from back in 2012 that it doesn’t make much difference. Simply choose the website structure that suits you or your client best. The same sentiment was echoed half a decade later by John Mueller, a search advocate officer for Google. 

Despite this, there is a continuing argument about which is actually better. At the end of the day, the issue is a technical one and does not really reflect a substantial structural difference in a website’s overall design.

In fact, it’s important (and interesting) to note that a subdomain can be converted to a subfolder. This seems to indicate that it doesn’t matter which you use in terms of SEO!

Why do some SEO professionals prefer subdomains?

One of the more pervasive misunderstandings is that a subdomain is viewed by a search engine algorithm as an entirely separate domain. Which, from an SEO perspective, would be a good thing. However, a subdomain in reality is actually looked at by search engines in the same way. The caveat to this would be if you’re using subdomains without connecting them with an internal link to your website. (More on that later.) If they’re not used as part of your main domain/website, they could be looked at as an entirely different website by Google.

To emphasise this importance, it’s worth remembering that there used to be a distinction between domains and subdomains. A website could have its main domain and its subdomains listed separately in search engine results pages (SERPs). This meant that huge conglomerates’ websites–from Disney to Amazon–could have any number of SERP listings.

It’s been a while since Google and other search engines updated their optimisation algorithms. Subdomains are now treated just like main domains. Nonetheless, the lessons from that time period seem to still be around.

Why do some SEO professionals prefer subfolders?

The preference for using subfolders for SEO does seem to have some backing in various case studies circulating around the internet. These cases are worth looking into as there are often other causation factors, whereas the use of subfolders seems more correlated with changes that improve SEO than anything else.

For example: A website that changes a subdomain to a subfolder and does nothing else is unlikely to see any change in their rankings. Once you start to build out those subfolders with more content (which in and of itself is optimised for keywords and search terms) you then start to see an improvement in traffic and rankings.

The takeaway? The move to the subfolder facilitated SEO strategies that helped improve the website’s performance. It didn’t cause the website’s results to pick up. 

Other case studies that seem to point to a preference for subfolders fail to take into consideration the fact that often subdomains aren’t linked internally, whereas subfolders are. The use of an internal link is going to cause the increase in traffic and rankings, not the subfolder itself.

When you take a look at these case studies that seemingly prove that subfolders are better than subdomains for SEO, take a closer look at the changes in website traffic. Is the traffic shifting around from page to page or is there genuine traffic growth across the website? It might seem obvious, but it can be easy to get confused and attribute changes in page traffic with real growth.

Further to this point, if a business changes and messes around with its subdomains and subfolders, you’re likely to see change in their traffic. Parts of the website are bound to increase (given a steady amount of continuous traffic) and other pages are likely to decrease. Measuring whether this is a successful SEO strategy will depend mostly on the company themselves and whether their strategy is oriented towards diverting that traffic. Only if the change of traffic for a page with increased views exceeds the change in traffic for a page with decreased views that you could confidently say that traffic overall increased. This doesn’t necessarily occur just by playing around with domains and folders.

Subdomain vs subfolder: understanding the changes in web traffic

Website traffic is certainly a useful and common way of measuring the success of an SEO campaign. When you trial using subdomains and subfolders on a website, chances are you will see some changes in web traffic that you’re tempted to ascribe to the new ‘sub’. There are, however, numerous potential causes you’d be wise to take the time to try and rule out.

1. Issues in pages being crawled

Google and other search engines are only able to crawl pages that are indexed and not-blocked. An incorrectly set up website with pages that can’t be crawled will obviously affect traffic and SEO.

2. Temporary changes

Google’s algorithm is a complicated and sophisticated beast. When you add, change or move pages on a website, it takes some time for Google to know what to do with it. Your traffic might change–up or down–as Google continuously crawls through and works out its ranking. You might be tempted to conclude the change a success or failure before long-term or permanent traffic has settled. 

3. Tracking methodologies 

Obvious but surprisingly ignored more often than you’d think, the way in which web traffic and SEO performance is tracked can be incorrect. There are variables that skew results that might not be taken into consideration like seasonal fluctuations, or even changes that are completely external like updates to the Google core. When analysing web traffic and SEO, all factors need to be considered before anything can be concluded with certainty.

4. Other factors

SEO is a complicated process. When you work on a website, each change you make to the platform can affect web traffic and rankings performance. Even non URL-specific adjustments or updates can cause changes. If your site’s performance speed or headings change, for example, your results can be affected. A big factor is content on a website. When content is removed or changed that brings in traffic, you’re likely to see a drop in numbers.

A final word on subdomains, subfolders and SEO

If it wasn’t obvious to you that SEO is a complicated business, it should be now. Subdomains have their pros and cons, as do subfolders. Neither are unambiguously better or worse for SEO. The best thing to do is the best thing for your specific website and business.

If you’re not sure what to do or want to know more about the subdomain vs subfolder divide in the SEO community, the GO Creative team can help! Don’t wait – contact us today!

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