Introduction
The canonical tag is probably something you have heard of if you have been trying to improve your website search presence. Canonical tags are one of the most straightforward yet potent SEO weapons in your arsenal — their potentially technical nature can be pretty intimidating.
Why are they important? Because using duplicate content creates confusion for search engines. When the same or nearly identical content appears at multiple URLs, Google might be unsure which page it should rank. This may divide your rankings & negatively affect your site.
Enter the canonical tag. Summary: For pages that exist in multiple versions, a canonical tag tells search engines which version of a page to consider as the primary version, helps to consolidate ranking signals, and solves duplicate content issues.
This blog will explain canonical tags, why they are essential for SEO, when and how to use them, and some best practices and common mistakes to avoid.
What is a Canonical Tag?
A canonical tag (or “rel=canonical” tag) is a piece of HTML that directs search engines to a page’s original or preferred version.
This is how it appears in HTML:
<link rel="canonical" href="https://example.com/page" />
Essentially, this tag tells search engines (and users) that the URL in the href attribute is the canonical version you want indexed and ranked.
Now, here are some common cases where canonical tags may come in handy:
- Variations of ecommerce products — a product like a t-shirt may have pages for color or for size, but the canonical tag all point to the master (main) product page.
- Tracking Parameters: UTM-tagged URLs or Session IDs can refer to the originating page.
- Related posts — posts covering related topics can reference a primary post.
Canonical Tags: How They Affect SEO?
Canonical tags address multiple issues in terms of SEO:
- This is a way to avoid duplicate content issues, and sure enough, Google never punishes for duplicate content, but can ignore or misrank the pages if it cannot figure out which page it should prioritize.
- Consolidates link equity (PageRank) — Canonical tags consolidate those signals to one version if a page has multiple versions that receive backlinks.
- Guiding search engine bots: A canonical is a powerful signal of your desired page, so you can get the version you want to see more.
- Redirected pages: Improves crawl efficiency – Search engines can crawl and index your site with fewer duplicate pages.
What to Use Canonical Tags For
Canonical Tags are not to be used on every page, but are essential in some situations:
- E-commerce sites with product variations
- E.g. /product-shoes-red, /product-shoes-blue → canonicals to /product-shoes
- E.g. /product-shoes-red, /product-shoes-blue → canonicals to /product-shoes
- Pages with UTM/tracking parameters
- Example: /blog-post?utm_source=facebook ➔ canonical = /blog-post
- Example: /blog-post?utm_source=facebook ➔ canonical = /blog-post
- HTTPS vs HTTP versions
- Canonical should point to the HTTPS version if both of these are implemented.
- Canonical should point to the HTTPS version if both of these are implemented.
- www vs non-www versions
- If they’re both live, create a canonical to the one you want to be your domain.
- If they’re both live, create a canonical to the one you want to be your domain.
- Related posts or category pages on the same blog
- If you have more than one blog on the same topic, point it to the most complete one.
- If you have more than one blog on the same topic, point it to the most complete one.
The Correct Way to Use Canonical Tags
Here’s how to set canonical tags for your sites:
Step 1: Determine duplicated or similar writings
- Finding duplicate pages with a tool like Screaming Frog or SEMrush.
Step 2: Select the preferred (canonical) URL
- Determine which version should win (generally the most thorough, SEO-optimized page).
Step 3: Add the canonical tag.
Example:
<link rel=”canonical” href=”https://example.com/page” />
Step 4: Use absolute URLs
- Use absolute URLs (https://example.com/page) instead of relative (/page) URLs.
Step 5: Test the implementation
- Use the Google Search Console (URL inspection tool) or third-party SEO crawlers to check.
Best Practices for Canonical Tags
- Always give your reference to the most pertinent version
- Do not select a random page; choose the one with the most substantial value.
- Avoid chaining
- As such, never create a chain like Page A → Page B → Page C; always point all duplicates to Page C directly.
- As such, never create a chain like Page A → Page B → Page C; always point all duplicates to Page C directly.
- Use self-referencing canonicals
- To avoid that confusion, every page should have a canonical tag and point to itself.
- To avoid that confusion, every page should have a canonical tag and point to itself.
- Ensure consistency
- The preferred URL should be the same in your sitemap, internal links and canonicals.
- The preferred URL should be the same in your sitemap, internal links and canonicals.
- Use 301 redirects when appropriate.
- As such, for tiny value pages, meaning a page that serves no real purpose, 301s are superior to canonical only tags.
- As such, for tiny value pages, meaning a page that serves no real purpose, 301s are superior to canonical only tags.
Common Mistakes to Avoid
- Redirecting all other pages to the homepage
- This absolutely ruins SEO visibility for other important pages.
- This absolutely ruins SEO visibility for other important pages.
- Mixing up canonical and noindex
- Canonical pulls in signals; noindex pulls a page from search. They serve different purposes.
- Canonical pulls in signals; noindex pulls a page from search. They serve different purposes.
- Using relative URLs
- It can lead to problems with indexing due to relative canonicals – Always use complete URLs.
- It can lead to problems with indexing due to relative canonicals – Always use complete URLs.
- Forgetting after site migration
- Canonical tags must also point to the new URLs at redesign or migration.
- Canonical tags must also point to the new URLs at redesign or migration.
How to Canonicalise Tags: Tools that Can Help with Canonical Tags
- Google Search Console — See the way Google indexes your pages.
- Screaming Frog SEO Spider: Find duplicated content and analyze canonicals.
- Ahrefs / SEMrush Site Audit – Monitor canonicalization problems at scale.
- Yoast SEO (WordPress plugin) — Easily add canonical tags without writing code.
Real-Life Examples
- E-commerce site with product variations
Let’s say you sell one shoe in 5 colors. Each variation has a separate URL, but the canonical tag for all variation pages points to the primary shoe product page. This allows the main product page to rank and not the duplicates. - Blog with paginated content
If && your blog is more than one page (/blog?page=1, /blog?page=2), you can use canonical tags to point to the first page or the category leading page to eliminate redundancy.
Conclusion
Canonical tags are a tiny piece of code, but they can have a massive impact on SEO. They help to ensure that search engines index the right pages, that you have no duplicate content issues, and to consolidate link equity, which are all vital to enhancing the visibility of your website.
To succeed with SEO, always:
- Find out the areas of duplicate content present on your site through auditing.
- Use self-referencing canonicals.
- Avoid common mistakes, like pointing all pages to the home page.
- Use tools like Google Search Console and Screaming Frog to validate.
A correctly implemented canonical tag will help you rank higher and make your site easy for the users to find, which way to go, and even mean the same thing for the search engines.
