Subdomain vs Subfolder for SEO: Which Structure Is Better?

The Debate That Won't Die

Should your blog, store, or help center live on a subdomain (blog.brand.com) or a subfolder (brand.com/blog)? SEOs have debated this for years. Here's what the data actually says.

Quick Definitions

• Subfolder (subdirectory): brand.com/blog, brand.com/store, brand.com/help
• Subdomain: blog.brand.com, store.brand.com, help.brand.com

Both are parts of the same domain, but search engines treat them differently.

What Google Says

Google has given mixed signals over the years. John Mueller has said Google can handle both and that it shouldn't matter much. However, Google also says it sometimes treats subdomains as separate sites for crawling and indexing purposes.

The official answer: "It mostly doesn't matter." The practical answer: it does.

What the Data Says

Multiple large-scale studies have consistently found:

• Subfolder content tends to rank better than equivalent subdomain content
• Moving from subdomain to subfolder typically increases organic traffic by 20-50%
• Domain authority consolidates in subfolders but fragments across subdomains

Notable case studies:

• HubSpot moved their blog from blog.hubspot.com to hubspot.com/blog and saw significant organic growth
• Moz recommended subfolders and practiced what they preached
• Monster.com moved career advice from a subdomain to a subfolder and saw traffic increase

Why Subfolders Usually Win

Authority Consolidation

Every piece of content on brand.com/blog builds the authority of brand.com. The backlinks to your blog posts strengthen your entire domain. With blog.brand.com, those backlinks primarily strengthen the subdomain, with less benefit flowing to the root domain.

Simpler Architecture

One domain, one sitemap, one Google Search Console property, one analytics setup. Subfolders are easier to manage technically.

Internal Linking

Links from brand.com/blog to brand.com/product are "internal" links within the same domain — they pass full link equity. Links from blog.brand.com to brand.com are technically "external" links between separate properties.

Crawl Efficiency

Google allocates a crawl budget per site. With subfolders, your entire site shares one crawl budget efficiently. With subdomains, each one gets its own allocation, potentially causing crawl issues.

When Subdomains Make Sense

Despite subfolders being the general recommendation, subdomains are better in specific situations:

Completely Different Applications

If your subdomain runs different technology (e.g., a SaaS app at app.brand.com while the marketing site runs on brand.com), subdomains provide necessary technical isolation.

International Versions

Subdomains for different countries (de.brand.com, jp.brand.com) can work when paired with proper hreflang tags and geotargeting in Search Console.

User-Generated Content

If users create content that could be low-quality or spammy, isolating it on a subdomain (community.brand.com) protects your main domain from quality signals.

Brand Separation

If a sub-brand or product line needs its own identity while remaining connected to the parent, a subdomain provides that balance.

Migration Guide: Subdomain to Subfolder

If you're currently on a subdomain and want to switch:

1. Map all existing URLs on the subdomain
2. Create matching subfolder URLs on the main domain
3. Set up 301 redirects from every subdomain URL to its subfolder equivalent
4. Update internal links across your site
5. Update Google Search Console — add the new subfolder content to your main property
6. Submit updated sitemap to Google
7. Monitor traffic for 4-8 weeks — expect a temporary dip followed by recovery and growth

Common Migration Mistakes

• Forgetting to redirect all pages (not just the homepage)
• Using 302 (temporary) redirects instead of 301 (permanent)
• Not updating canonical tags
• Removing the old subdomain before redirects are verified

The Bottom Line

For most businesses, subfolders are the better choice. They consolidate authority, simplify management, and consistently perform better in SEO studies.

Use subdomains only when technical requirements demand it. And regardless of your URL structure, make sure your domain itself is strong — check your brand name's availability across domains, social handles, and trademarks with BrandScout.