What is a Canonical Tag?
A canonical tag (rel="canonical") is an HTML element used to prevent duplicate content issues by specifying the preferred version of a web page. It tells search engines which version of a URL should be considered the primary one, helping with SEO ranking and avoiding content duplication penalties.
Example of a Canonical Tag:
<link rel="canonical" href="https://www.example.com/preferred-page-url/">
This tag is placed within the <head> section of the HTML code.
How to Fix Canonical Tag Issues?
If canonical tags are not implemented correctly, they can cause indexing issues. Here’s how to fix them:
1. Ensure Correct Placement:
The canonical tag should be inside the <head> section of your HTML.
2. Use Absolute URLs:
Always use the full URL (with https://) instead of relative URLs.
✅ Correct:
<link rel="canonical" href="https://www.example.com/page/">
❌ Incorrect:
<link rel="canonical" href="/page/">
3. Avoid Multiple Canonical Tags on the Same Page:
A page should have only one canonical tag.
4. Point to the Right Version (www vs. non-www, HTTP vs. HTTPS):
If your site uses HTTPS, ensure the canonical URL reflects this:
✅ https://www.example.com/ (if your site is using HTTPS)
5. Check for Redirect Conflicts:
If a page is redirected but has a different canonical tag, it confuses search engines.
Fix: Ensure the canonical URL matches the final destination after redirection.
6. Handle Pagination Properly:
If paginated pages (page-2, page-3) exist, avoid self-referencing canonical tags that all point to page 1.
Fix: Each paginated page should have its own self-referencing canonical tag.
7. Use Canonical Tags Instead of Noindex:
If you want search engines to index a page but consolidate link equity, use canonical tags instead of noindex.
How to Generate a Canonical Tag?
You can manually create canonical tags, but for larger websites, automated solutions are recommended.
1. Manually Add to HTML:
Add the following inside the <head> section of your web pages:
<link rel="canonical" href="https://www.example.com/your-page-url/">
2. Using WordPress (Yoast SEO, Rank Math, etc.):
Yoast SEO Plugin:
1. Edit a page or post.
2. Scroll down to the Yoast SEO section.
3. Click on the Advanced tab.
4. Add the preferred URL in the Canonical URL field.
Rank Math Plugin:
1. Edit a page or post.
2. Scroll down to the SEO Settings.
3. Enter the Canonical URL under the Advanced Settings.
3. Generate Canonical Tags Dynamically (For Developers)
If you’re working with a dynamic website, you can generate canonical tags automatically in CMS platforms like WordPress, Shopify, or custom-coded websites.
PHP Example for Dynamic Canonical Tags:
<link rel="canonical" href="https://www.example.com<?php echo $_SERVER['REQUEST_URI']; ?>">
JavaScript Example:
var canonicalTag = document.createElement("link");
canonicalTag.rel = "canonical";
canonicalTag.href = window.location.href;
document.head.appendChild(canonicalTag);
For Shopify:
Shopify automatically generates canonical tags, but you can override them by modifying the theme’s theme.liquid file.
How to Check If Canonical Tags Are Working?
1. View Page Source (CTRL + U)
Look for <link rel="canonical" href="https://www.example.com/page/">
2. Use Google Search Console
Under Coverage Report, check if Google has indexed the correct canonical version.
3. Use SEO Tools:
Screaming Frog SEO Spider
Ahrefs Site Audit
SEMrush Site Audit
4. Google’s URL Inspection Tool
Enter the URL in Google Search Console → Click Inspect → Check the canonical status.
Final Thoughts
Implementing canonical tags correctly can improve SEO byc onsolidating link signals and avoiding duplicate content penalties. Always ensure they are placed correctly, point to the right version, and are tested using SEO tools.