Subdomains and subfolders

There is a big difference between using subdomains, subfolders or separate domains to structure the content of your website. Read about the pros and cons of the different solutions here, so you can choose the best SEO solution.

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Subdomains and subdirectories from an SEO perspective

We are often asked whether you get the best results from your SEO efforts by structuring the content of its website using subdomains, subfolders or several different domains. In most cases, subfolders have the greatest SEO impact, but the truth is that subfolders are far from always the best solution.

Deciding how to structure your website depends on many different factors, and SEO is just one of them. User-friendliness, information architecture and positioning in the market also play a big role, so you would do well to consider carefully which solution is best for you and your business.


1. What is a domain?
2. What is a subdomain?
3. What is a subfolder?
4. Advantages of subdomains
5. Advantages of subfolders
6. Advantages of independent domains
7. Consider the pros and cons carefully
8. Be realistic

What is a domain?

A domain (or domain name) is a unique name that refers to your website. The domain is entered in the address bar of the internet browser and the user is then automatically redirected to your website. Domains can consist of letters, numbers and hyphens.

All domains are followed by a top level domain (TLD), which acts as a kind of categorisation of the domains. Examples of TLDs are .dk (Denmark), .se (Sweden), .edu (educational institutions) and .org (non-commercial organisations). It is generally not a requirement to use TLDs for their intended purpose. So you can own a .org domain even if you are a commercial organisation.

In Denmark the top level domain .dk is administered by DK Hostmaster. DK Hostmaster takes care of all the administrative and practical work related to the domains. The actual purchase of the domains takes place with a so-called registrar (en hosting provider) - approved by DK Hostmaster - where you typically also buy a server space for your website.

What is a subdomain?

And subdomain is a standalone domain that is linked to your main domain. The subdomain is specified in front of the main domain, separated by a period, so a web address with a subdomain has the following format: subdomain.domain.uk.

The texts www in most domain names (www.domæne.dk) is actually a subdomain. Unique subdomains act as a substitute for www, and therefore it is very rare to use both www and a unique subdomain in the same domain name.

A subdomain tells Google and your visitors that the content on the subdomain is separate from the content on the rest of your website. Subdomains are therefore often used to divide the content of a website into smaller, more manageable parts. For example, some people place their blog on a subdomain (blog.domain.dk).

Although the subdomain is a subdivision of your domain, Google interprets it as a separate website. This means that the SEO value of your main domain is transferred to your subdomain (and vice versa) only to a very limited extent. Therefore, when creating a subdomain, you need to start the SEO optimisation from scratch.

With most hosting companies, you can create an unlimited number of subdomains for free. The creation is usually done via your control panel and you will then be able to add content to the subdomain via a subdomain folder on your web server.

What is a subfolder?

En subfolder is a sub-section of your website that often contains related content. The subdirectory is named after the domain name, separated by a slash, and a web address with a subdirectory has the following format: domain.dk/subdirectory/.

Subfolders can be used to categorise content and to make the structural organisation of the website visible. For example, if you have different sections on your website, you can create a subfolder for the content in each section (domain.co.uk/section/content), making it visible to Google and your visitors which section the content belongs to.

Google interprets subdirectories as part of your domain, and therefore the SEO value is transferred from the main domain to all subdirectories. However, you still need to SEO optimise the content in the subdirectories because each content page is to some extent individually rated by Google.

You can easily create an unlimited number of subfolders on your web server - it's the same as creating folders on your computer. If you use a CMS system (for example WordPress or Joomla), subfolders are usually created automatically, in such a way that the subfolders reflect the menu structure of your website.

Advantages of subdomains

There are a number of SEO and user benefits to using subdomains rather than subfolders. The advantages of using subdomains are that they:

1. Enables multiple rankings in search results

Google limits the number of search results from the same domain, which means that a domain usually can appear a maximum of three times among the search results on the first page. If you create subdomains, you can increase the number of possible first page rankings because Google interprets each subdomain as a separate domain. However, don't assume that just because you create more subdomains, you will rank higher - mainly because you are unlikely to have many pages relevant to the same keyword or search phrase.

2. Enable relevant keywords in the domain name

Subdomains make it possible to include relevant keywords in the domain name. For example, if you sell travel and hotel accommodation, you can create a subdomain with the address travel.domain.dk and another with the address hotels.domain.dk. Relevant keywords in the domain name tell Google and your visitors what your website is about, and can help increase your website's credibility and authority. Of course, you can also include relevant keywords in subdirectory names, but keywords in subdomains have a higher SEO value.

3. Strengthens your global visibility

If your website targets users in different countries, it's important that the relevant parts of your website appear in Google in those countries. You can help Google determine your target audience by creating a subdomain for each language (e.g. uk.domain.com) and by using the International targeting in Google Search Console to tell Google which country each of your subdomains is targeting.

Subfolders can also be used for language versioning, and the "International targeting" feature in Google Search Console can also be used on subfolders. However, only subdomains can be forwarded to another web server. The redirection allows you to host each language version on a unique web server that is physically located close to your users. This gives search engines an extra signal about who your target audience is and improves website load time because the web server is located close to your users.

4. Strengthen the branding of your franchisees

If you have assigned the rights to your business system to one or more franchisees, it is a good idea to offer them a sub-domain under your main domain. This will give your franchisees their own website and make it clear to Google and visitors that they are part of your successful concept. By using sub-domains, you also have a degree of control over the franchisees' websites and you don't risk any SEO errors on their sub-domains negatively impacting your main domain.

5. Make your website more manageable

If your company is involved in several very different business areas, you can use subdomains to separate the business areas from each other. You can also use subdomains to separate and categorise large amounts of digital content. This will make your website more manageable, while making it easier to SEO-optimize the site for specific keywords and search phrases, because each subdomain focuses on one topic area.

6. Strengthens your position in new business areas

If you want to expand your business with new products that are radically different from those you offer now, it often makes sense to separate them from your established website. You can separate the products using subdomains, while signalling to Google and your visitors that your established brand is behind the products. In this way, you create credibility around your new products and you leverage the momentum associated with your brand.

7. Prevents software and speed problems

If you have a large website with a lot of visitors, you can easily run into problems with your website's load time, or with the interaction between the software and plugins you use. By splitting your website into several different sub-domains, each hosted on a different web server, you can often reduce the amount of software on each domain, thereby minimising the risk of conflicts. In addition, the speed of your main domain is not slowed down by any resource-heavy applications and plugins on your sub-domains.

8. Simplifies the splitting of the company

There can be many reasons for splitting a business into smaller parts. For example, an employee may want to buy parts of the business, or you and your co-owners may disagree about how to run the business in the future. If you have linked your different businesses into different sub-domains, it is very easy to sell off one of them because they are not directly integrated with each other.

Advantages of subfolders

There are also a number of SEO and user benefits to using subdirectories rather than subdomains. The advantages of using subdirectories are that they:

1. Inherits SEO value from the main domain

Subdirectories inherit SEO value from your main domain because search engines interpret subdirectories as a natural part of the domain. This means that content placed in subdirectories is more likely to rank well in search results than content placed on subdomains. So you save yourself a lot of SEO work by using subdirectories rather than subdomains. However, you still need to SEO optimise the content in the subdirectories because each content page is to some extent individually rated by Google.

2. Adds SEO value to your main domain

The more good content and the more visitors you have on your website, the more authority the website has and the better rankings it will usually achieve in search results. By placing content in subdirectories, you increase the amount of content on the domain, thereby strengthening the overall SEO value of the domain. At the same time, you strengthen the SEO value of the content in your other subdirectories, because the subdirectories inherit SEO value from the main domain. Subdirectories thus have a reinforcing SEO effect on each other.

3. Ensures meaningful organisation of content

Subdirectories are great for organising and categorising content into meaningful and descriptive URLs that clarify the website's structure for Google and your visitors. For example, if you have different sections on your website, you can create a subfolder for the content in each section (domain.co.uk/section/content), making it visible to Google and your visitors which section the content belongs to.

4. Has a high user-friendliness

Some users find it more natural to write URLs with subdirectories (domain.dk/subdirectory) rather than URLs with subdomains (subdomain.domain.dk). If you use a subdomain, there is also a risk that some users will mistakenly type www before the subdomain (www.subdomæne.domæne.dk), and you will lose the visitor because the URL is invalid.

5. Easy to set up and manage

Subdirectories are much easier to create and manage than subdomains. On your web server, you can create subfolders as easily as you create folders on your computer, and if you use a CMS system (for example WordPress or Joomla), subfolders are usually created automatically. Subdomains require more technical knowledge, and if the subdomains are hosted on different web servers, they also require more administrative work and costs.

Advantages of independent domains

Standalone domains have many of the same advantages as subdomains, because Google considers subdomains to be standalone domains. Therefore, from an SEO point of view, there is not much difference between using standalone domains and subdomains.

On a standalone domain, however, you have the option to choose a specific top level domain (TLD), and this can be an SEO advantage if you are targeting users in different countries. By using a TLD that corresponds to the country your website is targeting, you create security and recognisability for your visitors, and you also give Google an indication of who your website is targeting.

Standalone domains are often shorter than subdomains (which are always linked to a main domain), and therefore standalone domains are usually easier to remember. Standalone domains also have the advantage that they are not linked to one brand (a main domain) - so you can completely separate your websites.

On the other hand, standalone domains are both more expensive and significantly more time-consuming than subdomains, and it can take a long time for Google to index the content on your domain. It can also be very confusing for your visitors if you address them from many different and unrelated domains.

Although link building is one of the most important strategies in SEO, you won't gain much by spreading your content across a bunch of different domains and linking between them. In most cases, the effect is much greater if you aggregate the content and focus on creating one great website.

Consider the pros and cons carefully

Consider the pros and cons of using domains, subdomains and subdirectories carefully and relate them to your business and website. Make sure you choose the right solution from the start, because once you have implemented a solution, changing it can be both expensive and time-consuming.

Basically, the larger and more content-rich your website is, the more arguments there are for choosing subdomains over subfolders. Think of it this way: if your content could just as well be located on several different websites, then subdomains are probably the best solution. Standalone domains usually only make sense to use if you can benefit from using different TLDs.

The argument that should carry the most weight when making a decision is the argument that subdirectories inherit SEO value from the main domain (as opposed to subdomains). If you use subdomains or multiple domains, you will miss out on a lot of SEO value from your main domain and this can negatively affect your visibility in search engines. Read more Timo Reitnauer's blog post about how he lost almost half his visitors when he moved his blog from a subdirectory to a subdomain.

In many cases, subdomains and subfolders go hand in hand. For example, Tv2.dk uses subdomains to separate its sections (nyheder.tv2.dk, vejr.tv2.dk, etc.) and subfolders to separate the content in each section (nyheder.tv2.dk/udland, nyheder.tv2.dk/politics, etc.). Dr.dk has chosen a different solution, where it does not use sub-domains, but separates both sections and content using subfolders (dr.dk/news/politics, dr.dk/radio/channels etc.).

You can use hreflang (a so-called rel="alternate" tag) to display the correct regional web address in the search results. For example, if you have an English-language page eksempel.com and a Danish-language version on a subdomain da.eksempel.com, you can use an alternate tag to tell Google to show users from Denmark the corresponding Danish-language version and not the English-language version. In short, Google will swap the English search result for the Danish one if the user is from Denmark. The Danish (sub)domain does not inherit SEO value from the English subdomain. Read more about hreflang.

Be realistic

Be realistic about your own abilities and limitations! Subdomains and standalone domains require much more work - both technical, administrative and SEO - than subdirectories. Standalone domains, and in some cases subdomains, also have ongoing operational costs (unlike subdomains, which are free).

If you don't have the financial resources and technical skills in your company - and if you don't want to pay others to help you - subfolders are probably the best solution for your business.

Field compressed

Mark Molgaard

Partner & Senior SEO Specialist

Se forfatter

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Do you need help with search engine optimisation (SEO), or are you considering whether it makes sense for your business to focus on SEO? Contact Henning Madsen for a no-obligation discussion about your SEO project.

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