Subdomains vs. Subdirectories for SEO: Choosing the Best Structure

For most industrial B2B websites, a single, well-organized domain is all that’s needed to support SEO goals, technical functionality, and user experience. But when your business starts to grow—whether it’s launching new products, entering international markets, integrating with third-party tools, or adding eCommerce capabilities—your existing site structure may no longer serve you. That’s when the question arises: Should we use a subdomain or a subdirectory?

This isn’t just a technical question—it’s a strategic one. Your choice can directly influence search engine performance, domain authority, and how users engage with your site. In industrial marketing, a critical decision is often whether to use subdomains (e.g., blog.yourdomain.com) or subdirectories (e.g., yourdomain.com/blog). While both approaches have their place, choosing the right one can significantly affect your SEO strategy, site authority, and user experience.

This article explains the difference between subdomains and subdirectories, explores the impact of each on SEO, and helps you decide which approach best aligns with your organization’s long-term goals.

What Are Subdomains and Subdirectories?

Subdomains

A subdomain is a distinct, separate entity of your main domain. For example, if your main site is example.com, a subdomain could be shop.example.com or blog.example.com. Search engines often treat subdomains almost like independent websites, which can be advantageous when you need a distinctly branded or highly specialized content area.

• Examples:
  • blog.example.com for company news
  • shop.example.com for eCommerce
  • resources.example.com for technical documentation

Subdirectories

A subdirectory (or subfolder) is a structure under your main domain. Using the same examples above, a subdirectory approach might be example.com/blog or example.com/shop. This means everything lives under the same primary domain, potentially pooling authority and keeping your site experience more unified. In the absence of other intentional decisions, this is typically the format used on most websites.

• Examples:
  • example.com/blog
  • example.com/services
  • example.com/resources

The Importance of This Decision for SEO

Your site architecture affects how search engines crawl and interpret your content. It can also influence your visitors’ experience, which indirectly impacts your search performance through factors like dwell time, bounce rates, and conversion events. For industrial B2B companies that often cater to multiple decision-makers—engineers, procurement managers, or executives—ensuring a smooth, authoritative web presence is essential.

SEO Implications

Subdirectories: Advantages for SEO

1. Authority Consolidation
   By keeping all content under a single domain, you’re essentially pooling your backlinks and reputation metrics in one place. This approach can help your domain as a whole gain SEO momentum, especially important when you’re focusing on highly technical or niche-industrial keywords.
2. Link Equity Distribution
   When new pages are added as subdirectories, any inbound links benefit the main site. This can enhance rankings across sections of your site, making it easier for new or updated content to rank.
3. Simplified Management
   Managing content, analytics, and technical elements (like an SSL certificate) is more straightforward under a single domain. For many marketing teams—especially those juggling product lines and user segments—this simplicity can save time and reduce potential errors.
4. User Experience Benefits
   A consistent URL structure can help users intuitively navigate your site. Since industrial buyers often want quick, precise information, having a cohesive structure can boost user satisfaction and trust.

Subdomains: Potential Use Cases

1. Distinct Content Scenarios
   If your company offers a wide array of products or services that cater to vastly different audiences—say, heavy manufacturing equipment vs. software solutions—a subdomain may help you segment those audiences. In these cases, search engines often treat subdomains as entirely separate websites, each with its own domain authority and performance signals.
   That means SEO efforts on your main domain might not directly benefit the subdomain—and vice versa. As a result, each subdomain will likely require its own dedicated SEO strategy, with separate keyword targeting, link building, and content development plans tailored to its specific audience and goals.
2. Targeted User Experiences
   A subdomain allows you to develop a unique style, navigation, or technology stack separate from the main site. This can be advantageous if you’re rolling out a new product line or beta program, and want to create a completely separate experience.
3. Separate Business Entities
   Sometimes, B2B companies acquire or partner with other entities that still need a brand identity independent from the main domain. Using a subdomain can strike a balance between brand cohesion and differentiation.

Expert Opinions

Google’s Official Stance

Google’s official stance on subdomains vs. subdirectories is that they treat them equally for search ranking purposes. According to John Mueller, who coordinates Google Search Relations efforts, Google’s algorithms don’t inherently prefer subdomains over subdirectories or vice versa when ranking pages.

SEO Community Perspectives

Despite Google’s official stance, Windmill’s own SEO practitioners have observed that subdirectories often perform better in terms of SEO. This is because subdirectories share the authority of the main domain, which can be beneficial for overall site performance. However, Google maintains that the choice should be based on what makes the most sense for the website’s structure and content organization, rather than SEO considerations alone.

Making the Decision

When deciding between subdomains and subdirectories, consider the following factors:

• Scope of Content: Is the new content or functionality closely related to your main brand, or does it cater to an entirely separate audience?
• Long-Term Goals: Do you envision a unified brand experience, or will you eventually spin off the subdomain as its own brand, business segment, or website?
• SEO Strategy: Are you focusing on building authority for a single domain, or do you want to strategically separate different product lines or services?

Best Practices for Implementation

If you choose subdirectories, ensure that you:

• Maintain a clear site hierarchy with intuitive navigation (e.g., example.com/services, example.com/services/welding, etc.).
• Use internal linking effectively to guide users and search engines between content areas.
• Keep your metadata, page titles, and header tags consistent for easy crawling.

If you opt for subdomains, you’ll want to:

• Set up proper redirects and canonical tags to inform search engines of your structure.
• Link frequently between the main site and subdomain so neither is treated as completely separate.
• Track analytics separately but maintain an overview so you can see how each subdomain contributes to overall brand visibility.

Let Windmill Help You Build a Stronger, More Visible Website

Choosing between subdomains and subdirectories can feel like a nuanced decision, but it boils down to your specific objectives, content strategy, and target audience needs. For industrial B2B companies, where authority, trust, and clarity are crucial, subdirectories often provide a simpler path to SEO success. However, subdomains can offer distinct branding benefits and specialized user experiences when strategically deployed.

At Windmill Strategy, we specialize in helping industrial B2B companies navigate these types of technical marketing decisions. Our team understands how to align your site structure with both short-term lead generation and long-term SEO growth. If you’re ready to optimize your online presence and secure better visibility in the search results that matter most, contact us today to discuss the right approach for your business.

Frequently Asked Questions

How do subdomains affect SEO?

Subdomains can sometimes split your domain’s authority because search engines may treat them like separate entities. However, if properly configured and linked, they can still benefit your overall SEO strategy—especially in cases requiring unique experiences, keyword strategies, or brand distinctions.

Do subdomains hurt SEO?

They don’t inherently hurt SEO, but they can complicate your site structure. If you spread your resources thin—managing multiple subdomains without robust cross-linking—it can dilute your content’s SEO value. Mitigation strategies include ensuring each subdomain has clear internal links back to the primary domain and consistent branding.

Are subdirectories better for SEO?

For most websites, yes. Subdirectories allow you to pool all SEO efforts under one domain, often resulting in faster gains in search visibility. This is especially true if your content serves a similar audience or business purpose.

When should you use a subdomain instead of a subdirectory?

Subdomains make sense when you need a distinct user experience, handle separate business entities, or run fundamentally different content from your main site. Large organizations or those that cater to different markets may find it advantageous to place significantly diverse offerings on subdomains.