Canonical URL
Definition
The 'official' version of a page when duplicate or similar content exists at multiple URLs. Tells Google which version to index and rank.
What is a Canonical URL?
A canonical URL tells search engines which version of a page is the "master" copy when the same (or very similar) content exists at multiple URLs.
Why Canonicals Are Needed
The same content often exists at multiple URLs:
yoursite.com/pageyoursite.com/page/www.yoursite.com/pageyoursite.com/page?source=email
Without canonicals, Google might:
- Index the wrong version
- Split ranking signals between versions
- See it as duplicate content
How Canonicals Work
Add this tag in your page's <head>:
<link rel="canonical" href="https://yoursite.com/page" />
This tells Google: "This is the official URL. If you find this content elsewhere, credit this version."
When to Use Canonicals
Product Variations
Same product accessible via multiple category URLs.
Tracking Parameters
Same page with different URL parameters for analytics.
Mobile/Desktop Versions
If you have separate mobile pages (rare now).
Syndicated Content
Content republished on other sites pointing back to the original.
Canonical vs 301 Redirect
- Canonical: Both URLs work, but one is preferred
- 301 Redirect: Old URL sends users to new URL
Use redirects when you've actually moved content. Use canonicals when both URLs need to exist.
Checking Canonicals
View your page source and search for rel="canonical" to see what's set.