Subdomain vs. Subdirectory: Pros and Cons + Which is Best

Subdirectories are pages housed under a website, whereas subdomains are separate domains entirely. Subdirectories are preferred for SEO purposes, but subdomains can prevent issues like keyword cannibalization. Let’s break it down.

Subdomains and subdirectories are two options to organize the pages of your website. We spoke with two HawkSEM esteemed lead strategists, Yara Askar and Austin Lewis, to compare the key differences between and when to use each.

Subdomain vs subdirectory: What’s the difference?

Subdirectories act as subfolders, whereas subdomains are separate websites within your main domain.

If your website was a library, the subdirectories would be the shelves where you categorize your books (aka content). For example, “website.com/guides” or “website.com/shoes.”

A subdomain, on the other hand, is a separate website under your main domain. It’s a way to create different websites using a unique prefix before your domain name. For example, “blog.example.com” or “shop.example.com.”

Subdirectories

From an SEO perspective, subdirectories optimize your website’s structure. Search engines rely on well-organized content to understand your site’s hierarchy and topical relevance to searchers.

By using subdirectories, you’re providing search engines with clear signals about the organization and depth of your content.

But subdirectories aren’t just about making search engines happy.

They also benefit your users by creating a logical and intuitive site structure. When visitors can easily find what they’re looking for, they’re more likely to stay on your site, return in the future, and engage with your content.

Another SEO bonus? You can include targeted keywords in subdirectory names and incorporate them into your URL structure. This helps search engines better comprehend the context and relevance of the content within each subdirectory structure.

And finally, if you spend time building backlinks to a domain, it won’t carry over to a subdomain.

A subdirectory, on the other hand, lives within the root domain — so it benefits from the root domain’s SEO equity and can add to the overall website SEO value.

Pro tip: Worried about excessive subfolders confusing crawlers? Not to worry, Google has no issue crawling hundreds or even thousands of subdirectories. However, it’s still ideal to stay organized to offer a seamless browsing experience for users.

Google doesn’t technically favor one over the other when it comes to subdomains vs. subdirectories. (Image: Pexels)

Subdomains

A subdomain is a “child domain” (or an extension) of the root or “parent” domain. A subdirectory works like a root directory subfolder.

Think of a website as an apartment complex. The main domain (e.g., www.example.com) is the apartment building, while the subdomains (e.g., blog.example.com) are each unit inside.

Google is a great example of how subdomains work. You have Google.com, which is the parent domain, and then you have subdomains like maps.google.com, docs.google.com, and mail.google.com. All are entirely new sites with different looks, functions, and purposes.

From a search engine optimization standpoint, subdomains can be a powerful tool when you need to delineate keywords or content from each other — for example, a product support website vs a product page itself.

Presenting different content or functionalities under separate subdomains helps search engines better understand and categorize your website.

However, it’s important to note that managing multiple subdomains can be more complex than working with a single domain.

Each subdomain is treated as a separate entity by search engines, meaning you’ll need to invest time and effort into optimizing and managing each one individually.

While a subdomain is a child domain, it’s treated as a separate entity from the main parent domain.

Since subdomains are unique websites, they’ll require a separate content strategy and analytics and tracking tools, such as Google Analytics.

Subdomains vs. Subdirectories: Which one do I choose?

“Google isn’t going to punish you for hosting a second website on your domain,” says Lewis.

“However, in most cases, we prefer to use the subdirectory approach so that we can bundle all of our SEO signals together in the most powerful way possible.”

Lewis offers an example:

“When you split a blog onto a subdomain, you are splitting the topical authority across two websites, instead of bundling it together,” he explains.

“Typically, blog content should support pillar content with internal links to boost the topical authority and visibility of the pillar pages. And that doesn’t work when your blogs are on a separate site.”

Which option offers better SEO?

“It depends,” says Lewis.

“If the goal is to boost topical authority and overall SEO of a website, then we should use subdirectories. If the goal is to separate content by the intent of the user, then we want to use a subdomain.”

This helps keep current customers and market-qualified leads separated, using separate websites and support teams.”

Let’s break it down a bit further:

Subdirectory pros

• Consolidated authority: Subfolders reside within the main domain, sharing their domain authority, backlinks, and overall SEO strength. So any SEO efforts done for the main domain can benefit the subfolders as well and vice versa. By consolidating authority, you can strengthen your website’s overall visibility in search engine rankings. Moving a blog to a subdomain would require rebuilding authority, backlinks, age of the domain, internal linking profile, etc.
• Shared SEO efforts: Managing a single website with subfolders allows you to concentrate your SEO efforts on a unified entity. You can focus on creating high-quality content, optimizing on-page elements, and obtaining backlinks without duplicating work across multiple websites. This approach saves time and resources while maximizing the impact of our SEO strategies.
• Link equity: When other websites link to your content, they pass on link equity, which can boost your search rankings. With subfolders, any backlinks acquired for one page or section of your website contribute to the overall authority and visibility of the entire domain. In contrast, with subdomains, backlinks earned for one subdomain do not directly benefit the main domain or other subdomains.
• User trust and consistency: By using subfolders, users stay within the main domain as they navigate between different sections. This consistent user experience enhances trust and reduces confusion, as users are familiar with the domain and its branding. In contrast, subdomains can create a fragmented user experience, often leading to lower user engagement which can potentially impact SEO metrics.
• Content organization and site architecture: Subfolders provide a logical and organized structure for your website’s content. It allows for better site architecture, easier navigation, and improved user experience. Additionally, search engines can understand the hierarchical relationship between subfolders and the main domain, leading to better indexation and crawlability.

Subfolder Cons

• Less flexibility: Subdirectories may provide less flexibility for customizing the design, functionality, and content for each section of your website.
• Disorganization: If subdirectories aren’t used correctly, they can make it harder for users to find what they want. For example, if a website has articles on different topics scattered across multiple subdirectories, users may struggle to locate the articles they’re interested in. Ideally, you should have main categories as subdirectories, like “Technology,” “Health,” “Travel,” or “Food.”

Subdomain pros

• Targeted optimization: Each subdomain can be optimized for specific keywords, audiences, or purposes, allowing you to tailor your SEO strategy and improve visibility in search engine results.
• Flexibility: Subdomains provide the flexibility to create separate mini-websites or sections within your top-level domain, allowing you to customize the design, functionality, and content for each subdomain.
• Branding opportunities: Subdomains can provide branding opportunities by creating a consistent and memorable presence for specific sections of your website, such as a blog or an ecommerce store.
• Localization: If you have a global presence, subdomains can be used instead of different websites to target various regions or languages. This allows you to provide localized content and better target specific audiences.
• Budget-friendly: Subdomains also allow you to keep costs down since you don’t need to purchase another domain. Plus, you can connect software you use at no additional cost, such as Teachable, Shopify, and ClickFunnels.

Subdomain cons

• Technical complexity: Managing multiple subdomains can be more complex and time-consuming than managing a single domain, as each subdomain generally requires separate hosting, configuration, and maintenance.
• Diluted authority: Subdomains are treated as separate entities by search engines, meaning the authority, backlinks, and domain reputation may be divided among multiple subdomains, potentially impacting overall SEO performance. This is a negative if you have a subdomain that’s similar to your main site that could use the SEO juice.
• Cross-subdomain tracking: Tracking user behavior and data across different subdomains can be challenging, requiring additional configuration and setup to ensure proper tracking for analytics and marketing purposes.
• Additional costs: When you create subdomains, you must pay for web developers and subscription fees.
• Maintenance and updates: Making changes or updates across multiple subdomains may require more effort and coordination, as updates may need to be implemented individually for each subdomain.

Use cases for subdomains and subdirectories

While subdirectories are typically the preferred option, there are several reasons to use a subdomain instead. Let’s explore why you may use one over the other.

Different use cases for subdomains:

• Adding an ecommerce store: Subdomains may be used to create a separate online store from the main website instead of creating separate websites. This allows for a specialized design, different hosting, and custom features distinct from the rest of the site.
• Creating localized sections: Subdomains can be used to create sections for different regions or languages. This helps target local audiences and provide more relevant information and content for each locale.
• Product support pages: This is beneficial in helping to prevent keyword cannibalization,” Lewis explains, “and also delineating the intent of your content.”

Different use cases for subdirectories:

• Organizing content: Subdirectories can also be used to organize large amounts of content into relevant.
• Improving SEO: Organizing content into subdirectories can help search engines better understand the structure of your website and deliver more relevant results.
• Showcasing specific products or services: Subdirectories can help highlight and showcase specific products or services, allowing you to better target customers and increase conversions.

How do subdomains and subdirectories affect blogs?

Subdomains make sense in some instances. For example, when a company has a niche industry, audience, or keyword they want to target that’s different from their “root” or main targets.

This also applies if the subdomain is intended to represent a completely different business or division from the root domain, such as a SaaS company that also runs an online vendor marketplace.

In most cases, however, sites target the same audience with their blogs as they would with the root domain. Their content strategy is also likely intended to serve the same business. In that case, it’s best to host a blog as a subdirectory.

Hosting your blog as a subdirectory can allow you to:

• Increase organic traffic to the root domain
• Organize content in a way that makes it easy for bots to manage and crawl
• Optimize content on the site without pages that compete with each other
• Streamline analytics by housing all metrics on a single domain

Subdomains can be useful for blogs if there’s a large content campaign that is slated to receive a lot of traffic and thus requires its own hierarchy path. (Image: Unsplash)

How subdomains and subdirectories affect search rankings: Case study examples

The HotPads blog was first on a subdomain and then moved to a subdirectory. Here are the results:

(Image: X)

The traffic increased exponentially, indicating Google values subdirectories for blogs.

Note that this worked for a blog, but may not necessarily achieve the same results for a different type of website.

Increasing SERP ranking by switching from subdomain to subdirectory

Then you have a site owner who built a blog called Vicara. Over the years, he built a stream of backlinks pointing to the primary domain. Before the switch, the blog was on a subdomain and was ranked in the top 100.

No matter what he did, he couldn’t get a better ranking. So he decided to switch to a subdirectory. He set up a new WordPress blog as a subdirectory and exported the content from the subdomain, then set up 301 redirects.

His goal was to prove whether using subdirectories was a ranking factor in Google’s algorithms.

After two weeks (to allow Google to index all of the new blog content), the blog’s position rose to position 57.

But, don’t throw out subdomains for blogs just yet.

The same webmaster did another test in 2021. He moved his blog from the primary domain to a subdomain and saw the opposite happen.

Increasing site ranking and visits after subdirectory implementation

VIOS Fertility, an IVF lab and fertility clinic, partnered with HawkSEM to help with its visibility online. Soon after, it merged with KindBody and immediately needed to merge the two sites.

Our focus went to rebranding and building an organized subdirectory architecture for the migration. In doing so:

• VIOS Fertility/Kindbody experienced a remarkable 74% increase in the total number of terms ranking for their website. This improvement in search rankings expanded their online visibility and reach.
• New organic users to the website saw an impressive 128% increase, indicating improved organic traffic and an expanded audience.
• The number of organic website sessions also increased by 128%, demonstrating that the migration and rebranding efforts successfully attracted more visitors to the website.

The takeaway

Askar explains, “Choosing when to use subdomains and subdirectories for a blog is a highly debated topic in the SEO world.”

Ultimately, you want to pick what’s best and most efficient for your site and business goals.

Subdomains provide the ability to target a different audience. Subdirectories allow sites to improve their overall SEO traffic to the main domain.

If you’re considering switching from a subdomain to a subdirectory, or vice versa, and want professional help, then reach out to HawkSEM’s SEO experts today.

This article has been updated and was originally published in October 2021.