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Canonical Tag

Canonical tags play a crucial role in addressing duplicate content issues and ensuring that search engines understand the preferred version of a web page. This explanation delves into the meaning of canonical tags, their significance in SEO, and best practices for their implementation.

What is a Canonical Tag?

A canonical tag (rel=”canonical”) is an HTML element used to indicate to search engines the preferred version of a web page when multiple versions exist. It helps prevent duplicate content issues by telling search engines which version to index and assign link equity. The canonical tag is added to the head section of a web page’s HTML code, pointing to the preferred URL.

Why Canonical Tags Matter for SEO

Duplicate content can negatively impact a website’s SEO performance. Here are some reasons why canonical tags are essential in SEO:

Consolidating Link Equity

When multiple versions of a web page exist, link equity can be diluted, as inbound links might point to different versions of the same content. Canonical tags help consolidate link equity by guiding search engines to the preferred version, ultimately improving its search ranking.

Preventing Duplicate Content Penalties

Although search engines, like Google, do not explicitly penalize websites for duplicate content, they may filter out similar pages from search results. Canonical tags help prevent this by signaling the preferred version to search engines, ensuring it ranks properly.

Enhancing Crawl Budget Efficiency

Search engine crawlers have a limited “crawl budget” for each website. Duplicate content consumes crawl budget, which could be better spent on discovering new or updated content. Canonical tags help search engines understand which pages to prioritize, making crawling more efficient.

Examples of Canonical Tag Use

Here are some common scenarios where canonical tags can be effectively used:


When a long article or product list is divided into multiple pages, search engines might perceive these as duplicate content. A canonical tag can be added to each paginated page, pointing to the main page or the preferred version, ensuring proper indexing and link equity consolidation.

URL Parameters

URL parameters, such as tracking codes or session IDs, can create multiple versions of the same page. A canonical tag can be used to inform search engines which version should be indexed.

HTTP and HTTPS Versions

If both HTTP and HTTPS versions of a page exist, a canonical tag should be used to indicate the preferred version (usually HTTPS) to avoid duplicate content issues.

Canonical Tag Best Practices

To effectively use canonical tags in SEO, follow these best practices:

Self-Referential Canonical Tags

Include a self-referential canonical tag on each page, pointing to its own URL. This ensures that any URL variations generated by parameters or other factors are still recognized as the canonical version.

Consistent Internal Linking

Ensure internal links consistently point to the canonical version of a page, reinforcing the preferred URL for search engines.

Use Absolute URLs

Use absolute URLs instead of relative URLs in your canonical tags to avoid potential misinterpretation by search engines.

Verify Canonical Tags

Regularly check your canonical tags to ensure they are pointing to the correct URLs and are implemented correctly. Tools like Screaming Frog can help audit your canonical tags.

In conclusion, canonical tags play a vital role in SEO by addressing duplicate content issues, consolidating link equity, and ensuring search engines index the preferred version of a web page.

By understanding the importance of canonical tags and implementing them correctly, you can enhance your website’s SEO performance and maintain a strong online presence.