WWW vs Non-WWW: Complete Canonicalization Guide 2025
Choosing between www and non-www versions of your domain is crucial for SEO success. This comprehensive guide covers domain canonicalization best practices, redirect implementation, and how to avoid duplicate content penalties that can hurt your search rankings.
What is Domain Canonicalization?
Domain canonicalization is the process of choosing a preferred version of your domain name (www vs non-www) and consistently directing all traffic to that version. Without proper canonicalization, search engines see your site as having duplicate content across multiple domains.
The Problem:
• example.com and www.example.com are technically different domains
• Search engines may index both versions, splitting your SEO value
• Users might bookmark different versions, creating inconsistency
• Analytics and tracking can be fragmented across versions
The Solution: Choose one canonical version and redirect all other versions to it using 301 permanent redirects.
WWW vs Non-WWW: The Great Debate
Both www and non-www versions have their advantages. The key is consistency, not which version you choose.
Non-WWW (Apex Domain)
✅ Advantages:
- • Shorter, cleaner URLs
- • Modern, minimalist appearance
- • Easier to remember and type
- • Popular among tech companies
- • Saves characters in social media
❌ Disadvantages:
- • Limited CNAME flexibility
- • Some DNS limitations
- • CDN setup can be complex
WWW (Subdomain)
✅ Advantages:
- • Better DNS flexibility
- • Easier CDN configuration
- • Cookie domain control
- • Traditional web standard
- • Load balancing advantages
❌ Disadvantages:
- • Longer URLs
- • Perceived as outdated
- • Extra characters to type
Popular Examples: Google (google.com), Facebook (facebook.com), and Twitter (twitter.com) use non-www, while BBC (www.bbc.com), CNN (www.cnn.com), and many e-commerce sites use www.
SEO Impact of Poor Canonicalization
Improper domain canonicalization can significantly harm your search engine rankings and organic traffic.
Duplicate Content Penalties
Search engines may see identical content on both www and non-www versions, potentially triggering duplicate content penalties and diluting your page authority.
Split Link Authority
Backlinks may point to both versions, splitting your link authority between www.example.com and example.com instead of consolidating it.
Analytics Fragmentation
Traffic data may be split across both domain versions, making it difficult to accurately analyze your website performance.
Indexing Issues
Search engines might index the wrong version or inconsistently index pages, affecting your search visibility.
Choosing Your Canonical Version
Consider these factors when deciding between www and non-www for your canonical domain:
Technical Considerations:
| Factor | Non-WWW | WWW |
|---|---|---|
| URL Length | Shorter ✓ | Longer |
| DNS Flexibility | Limited | Better ✓ |
| CDN Setup | Complex | Easier ✓ |
| Cookie Control | Limited | Better ✓ |
| Modern Appeal | Higher ✓ | Traditional |
Decision Framework:
Choose Non-WWW if:
- You prefer shorter, cleaner URLs
- Your site is simple without complex CDN needs
- You want a modern, minimalist brand image
- Social media character limits matter to you
Choose WWW if:
- You need advanced DNS configuration flexibility
- You use multiple CDNs or complex hosting setups
- You require granular cookie domain control
- You have existing strong www branding
Implementing Redirects
Once you've chosen your canonical version, implement 301 permanent redirects to ensure all traffic goes to your preferred domain. Learn more about redirect types in our 301 vs 302 guide.
Redirecting to Non-WWW (example.com):
Apache (.htaccess):
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.example\.com$ [NC]
RewriteRule ^(.*)$ https://example.com/$1 [R=301,L]
# Alternative method
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\. [NC]
RewriteRule ^(.*)$ https://example.com/$1 [R=301,L]Nginx:
server {
listen 80;
listen 443 ssl;
server_name www.example.com;
return 301 https://example.com$request_uri;
}Redirecting to WWW (www.example.com):
Apache (.htaccess):
RewriteEngine On
RewriteCond %{HTTP_HOST} ^example\.com$ [NC]
RewriteRule ^(.*)$ https://www.example.com/$1 [R=301,L]
# Alternative method
RewriteEngine On
RewriteCond %{HTTP_HOST} ^(?!www\.) [NC]
RewriteRule ^(.*)$ https://www.example.com/$1 [R=301,L]Nginx:
server {
listen 80;
listen 443 ssl;
server_name example.com;
return 301 https://www.example.com$request_uri;
}PHP Implementation:
Important: Always use HTTPS in your canonical URLs and ensure your SSL certificate covers both www and non-www versions (or use a wildcard certificate).
Google Search Console Configuration
Configure Google Search Console to recognize your preferred canonical domain and monitor both versions during the transition.
Step 1: Add Both Properties
Add both www and non-www versions as separate properties in Search Console:
https://example.comhttps://www.example.com
Step 2: Set Preferred Domain (Legacy)
While Google removed the preferred domain setting in 2019, proper redirects and canonical tags now handle canonicalization automatically.
Note: Google now relies on redirects, canonical tags, and consistent internal linking to determine your preferred domain version.
Step 3: Monitor Both Properties
Keep both properties active to monitor:
- Redirect implementation success
- Crawl errors on either version
- Index status changes
- Mobile usability issues
Testing and Verification
Thoroughly test your canonicalization setup to ensure it works correctly across all scenarios.
Essential Tests:
Testing Tools:
Browser Developer Tools
Inspect Network tab for redirect status codes
F12 → Network → Check redirect responses
Pro Tip: Test your redirects from different locations and devices to ensure consistency. Clear browser cache between tests for accurate results.
Common Mistakes to Avoid
❌ Using 302 Instead of 301 Redirects
Problem: Temporary redirects don't pass SEO value and confuse search engines about your canonical preference.
Solution: Always use 301 permanent redirects for canonicalization.
❌ Inconsistent Internal Linking
Problem: Mixing www and non-www in internal links sends conflicting signals to search engines.
Solution: Update all internal links to use your canonical domain consistently.
❌ Forgetting SSL Certificate Coverage
Problem: SSL certificate doesn't cover both www and non-www versions, causing security warnings.
Solution: Ensure your SSL certificate covers both versions or use a wildcard certificate.
❌ Not Updating Canonical Tags
Problem: Canonical tags still point to the non-preferred domain version.
Solution: Update all canonical tags to point to your chosen canonical domain.
❌ Redirect Chains
Problem: HTTP→HTTPS→canonical creates unnecessary redirect chains.
Solution: Redirect directly to the final canonical HTTPS version in one step.
Changing Your Canonical Domain
If you need to switch from www to non-www (or vice versa) on an existing website, follow this careful migration process:
Phase 1: Preparation (Week 1)
- Audit current traffic and ranking data
- Backup website and server configurations
- Plan implementation during low-traffic periods
- Notify stakeholders about the change
Phase 2: Implementation (Week 2)
- Implement 301 redirects from old to new canonical domain
- Update all internal links to new canonical domain
- Update canonical tags and XML sitemaps
- Configure both versions in Google Search Console
Phase 3: Monitoring (Weeks 3-8)
- Monitor Search Console for crawl errors
- Track organic traffic and ranking changes
- Update social media profiles and external listings
- Contact important external sites for link updates
Expected Timeline: Search engines typically recognize canonical domain changes within 4-8 weeks. Monitor closely and be patient during the transition period.