Subdomain vs Subdirectory: Which One Belongs on Your Site?

8-minute read

Subdomain vs Subdirectory: Making the Right Choice for Your SEO Strategy

When building or restructuring your website, you’ll inevitably face a critical decision that can significantly impact your SEO performance: should you use a subdomain or subdirectory? This choice might seem like a minor technical detail, but it can have far-reaching consequences for your search visibility, user experience, and overall marketing strategy.

As businesses increasingly compete for digital visibility, understanding the implications of your website’s URL structure becomes essential. Let’s unpack this complex topic and provide you with the insights needed to make an informed decision for your specific situation.

Table of Contents

• The Basics: Understanding Subdomains and Subdirectories
• Key Differences Between Subdomains and Subdirectories
• SEO Impact: How Your Choice Affects Rankings
• When to Use a Subdomain vs. Subdirectory
• Implementation Best Practices
• Real-World Examples and Case Studies
• Migrating Between Structures
• Frequently Asked Questions

The Basics: Understanding Subdomains and Subdirectories

Before diving into the strategic implications, let’s clarify what these terms actually mean:

What is a Subdomain?

A subdomain is a separate section of your website that exists as part of your main domain but is treated somewhat independently by search engines. It appears before your root domain name in the URL structure.

Example: blog.example.com (where “blog” is the subdomain of example.com)

What is a Subdirectory?

A subdirectory (also called a subfolder) is a section within your main website. It appears after your domain name in the URL structure and is generally perceived as part of your main website by search engines.

Example: example.com/blog/ (where “blog” is a subdirectory of example.com)

Key Differences Between Subdomains and Subdirectories

While both structures can organize content, they differ in several important ways:

Authority and Link Equity

One of the most significant differences relates to how search engines distribute authority:

• Subdirectories generally share the domain authority of the main website, making it easier for new content to rank if the main domain already has established authority.
• Subdomains may be treated as separate entities by search engines, requiring them to build their own authority. However, some link value is still passed from the main domain.

Technical Implementation

The setup process varies considerably:

• Subdirectories are easier to implement as they’re simply folders within your existing website structure.
• Subdomains require additional DNS configuration and often separate hosting setups.

Content Segregation and Branding

Your organizational needs may determine which structure works best:

• Subdirectories keep everything under one roof, reinforcing a unified brand.
• Subdomains allow for distinct branding and separate experiences that still connect to your main brand.

SEO Impact: How Your Choice Affects Rankings

The subdomain vs subdirectory debate matters most for its SEO implications:

Domain Authority Distribution

When it comes to how search engines evaluate your site:

• Subdirectories typically benefit from the cumulative SEO value of your entire domain. All backlinks to any part of your site contribute to the overall authority that each subdirectory can leverage.
• Subdomains may need to establish authority more independently. While Google has stated they can understand the relationship between a subdomain and its parent domain, practical evidence suggests subdomains don’t always benefit from the full authority of the main domain.

Keyword Targeting and Content Relevance

Your structure influences how search engines understand your content focus:

• Subdirectories help reinforce the overall topical relevance of your domain, potentially boosting rankings for related terms across your site.
• Subdomains can allow you to target distinctly different audiences or topics without diluting the focus of your main domain.

When to Use a Subdomain vs. Subdirectory

There’s no one-size-fits-all answer. Your decision should depend on specific circumstances:

When to Choose a Subdomain

Consider using a subdomain when:

• You’re creating content that targets a completely different audience or topic
• You need a separate technical infrastructure (like a different CMS)
• You want a distinct user experience or branding
• You’re creating an international version of your site
• You have a large-scale web application that functions differently from your main site

When to Choose a Subdirectory

Opt for a subdirectory when:

• The content is closely related to your main site’s focus
• You want to maximize the SEO benefits of your existing domain authority
• You want simpler analytics tracking and implementation
• You’re adding a blog or resources section that complements your main offering
• You have limited technical resources for maintenance

Implementation Best Practices

Regardless of which structure you choose, follow these best practices:

Technical SEO Considerations

• XML Sitemaps: Create comprehensive sitemaps for either structure and submit them to search engines
• Robots.txt: Configure appropriately to ensure proper crawling
• Canonical Tags: Use these to prevent duplicate content issues, especially if similar content exists across subdomains
• Internal Linking: Maintain strong internal linking between all sections of your site

Analytics and Tracking

Ensure proper measurement across your site:

• For subdomains, configure cross-domain tracking in analytics platforms
• Set up property-wide search console monitoring
• Create segment-specific reports to track performance separately

Real-World Examples and Case Studies

Let’s examine how different businesses have approached this decision:

Success with Subdirectories

Many major brands have consolidated previously separated content into subdirectories with positive results:

• HubSpot: Moved their blog from blog.hubspot.com to hubspot.com/blog and saw significant traffic increases
• Buffer: Transitioned various content sections to subdirectories to strengthen their main domain

Effective Subdomain Implementation

Some companies successfully leverage subdomains for specific strategic purposes:

• GitHub: Uses username.github.io for user pages, creating a scalable system for millions of project pages
• Shopify: Uses independent stores on subdomains like store.myshopify.com to separate merchant storefronts

Migrating Between Structures

If you’re considering changing your current structure, proceed carefully:

Migration Planning

• Conduct a comprehensive content and URL audit
• Create a detailed 301 redirect mapping
• Update all internal links throughout your website
• Plan for temporary traffic fluctuations during the transition
• Monitor rankings closely after migration

Common Migration Pitfalls

Avoid these mistakes when changing your structure:

• Inadequate redirect planning leading to 404 errors
• Forgetting to update internal links
• Not informing search engines of the changes through Search Console
• Implementing changes without staging environment testing

Frequently Asked Questions

Does Google treat subdomains and subdirectories differently?

While Google has stated they can understand the relationship between a subdomain and its main domain, practical experience suggests subdirectories more reliably share the authority of the main domain. Google’s John Mueller has said that Google’s systems generally can figure out the relationship, but many SEO professionals observe that subdirectories typically perform better for content closely related to the main site.

Will moving from a subdomain to a subdirectory improve my SEO?

It depends on your specific situation. Many companies have seen SEO benefits from moving content from subdomains to subdirectories, particularly when the content is closely related to their main offering. However, the migration process itself carries risks, and not all sites will see the same results.

Can I use both subdomains and subdirectories on the same website?

Yes, many websites use a hybrid approach, with subdirectories for closely related content and subdomains for distinctly different sections or applications. The key is making strategically sound decisions based on your specific content and audience needs.

How do subdomains and subdirectories affect local SEO?

For local SEO, subdirectories are generally preferred for location pages (example.com/locations/city-name/) as they consolidate domain authority. Subdomains for different locations might make sense only for very large operations with distinct local operations and separate teams managing each location’s content.

Will changing my structure affect my current rankings?

Yes, any major URL structure change can temporarily impact rankings. With proper 301 redirects and careful implementation, these effects can be minimized, but expect some fluctuations during the transition period before stabilizing.

Making the Right Choice for Your Business

The subdomain vs subdirectory decision ultimately comes down to your specific business needs, marketing goals, and technical considerations. While subdirectories generally offer SEO advantages for most content types, subdomains provide benefits in specific scenarios where content or functionality differs significantly from your main website.

Remember these key points:

• Subdirectories typically share domain authority more effectively
• Subdomains offer greater separation when needed for technical or branding reasons
• Implementation and maintenance complexity differs between the two options
• The best choice depends on your specific content strategy and business goals

Whether you’re building a new website or considering restructuring an existing one, take the time to evaluate how your URL structure aligns with both your short-term marketing objectives and long-term business strategy.