The Canonical Day (also rel=canonical ) is a small snippet of HTML code in the <head>area of a website that gives a clear recommendation to search engines which URL as preferred version a page should be viewed. In practice, it is primarily used to avoid duplicate content — i.e. duplicate or very similar content on different URLs. Why is that important? Duplicate content can confuse search engines, unnecessarily inflate indexing and, in the worst case, result in the wrong side appears in search results. Studies show that almost 30% of all content on the web is duplicate content (source: Raven Tools) — an enormous amount that underscores the need for effective solutions.
Search engines such as Google, Bing & Co. introduced the Canonical Tag back in 2009 to give website operators a tool against such duplicate content. SEO managers, marketing managers and online shop operators are often confronted with the topic in practice: Similar or identical content can quickly end up on the website in multiple versions for technical reasons. This is where the Canonical Tag comes in to provide clarity for search engines. ESR signals:”Hey Google, this is the main page — index it preferably!“. The canonical tag thus makes a significant contribution to saving crawl budget, bundling ranking signals and ensuring optimal user navigation.
Before we go into detail, you should know: The Canonical Tag is not rocket science, but an essential standard in the search engine optimisation of modern websites — especially for larger online shops or content websites. In this guide, you will learn everything you need to know in a locker-professional manner: from typical use cases and common mistakes to best practices, tools and strategic tricks. Let's get started!
In which situations is the Canonical Tag used? Whenever multiple URLs offer very similar content. Here are some typical use cases from practice (from e-commerce to B2B):
In short: Wherever the same or very similar content appears at multiple addresses, the Canonical Tag is worth its weight in gold. It protects against cannibalisation of your own content and ensures that only the most relevant version ends up in the Google index.
As useful as Canonical Day is — in practice, we unfortunately also see many SEO consultants implementation failure and misunderstandings. Here are the most common pitfalls so that you can avoid them in your project:
As you can see, the devil is in the details. Many of these mistakes are technical in nature, others are created by incorrect assumptions. Fortunately, you can avoid them all if you know about them — and that's exactly why you're reading this guide!
Now that we know what can go wrong, the question is: How do you do it right? Here are best practices for working with Canonical tags—as well as tools to help you review and monitor implementation:
Each indexable page gets a self-referencing canonical: It has been tried and tested to set a canonical tag on all important pages that points to yourself when the page should be indexed below itself. Example: the start page contains <link rel="canonical” href=”https://www.example.com/“>. Such a self-canonical creates clarity. If duplicates of this page are accidentally created at some point, Google immediately knows which URL is the right one. Modern CMS often use self-referencing canonicals by default — you should still check it.
Consistently point duplicates to main URL: In cases of duplicate content (see use cases above), a version should always be set as canonical. All other duplicate URLs point to this master version via a canonical tag. For example, for product variants, every size/color URL points to the product.html without parameters. Important: The canonical page itself links On yourself (see point above). This creates a clean canonical chain without breaks.
Use absolute URL in canonical: The href address in the canonical tag should ideally be specified as a full URL (including https://...). Relative paths could also work in theory, but there is a risk of errors. consistent use of www or non-www, Trailing Slashes etc. is also part of a consistent strategy — the canonical URL should be written exactly as the preferred index URL should look.
No canonicals on paginated pages one below the other (unless useful): With Pagination (e.g. page 2 of an article list) do not blunt canonicalise all pages on page 1 — there are other solutions for this, such as rel="prev/next”. However, this is also no longer recommended by Google. Preferably, or you can leave all pages indexable. Google recognises the paginated pages as belonging together, provided that they have an independent value. Canonical can be used here if, for example, pages 2—N have very thin content and you only want to make expli rank page 1, but that is advanced and requires caution.
Combination with hreflang: The following applies to multilingual websites: Different language versions not Merge via Canonical (unless there are 1:1 duplicates in the same language). Instead, you use hreflang to tell Google the language and country variants. Canonical is only used here if eine The language version is the preferred one and the other is really superfluous (e.g. identical English content on .com and.co.uk — here you could canonicalise one on top of the other, although it would be cleaner to take one version offline).
Conduct audits regularly: Websites are alive — updates, new features or team changes can subconsciously undermine the Canonical strategy. Therefore, plan regular SEO audits one to check canonical tags. Especially during relaunches, attention should be paid to correct canonicals.
Google Search Console (GSC): The most important tool for verifying Canonicals is the free Google Search Console. In the GSC, you can go to “Indexing” resp “Pages” See which URLs have been indexed and whether Google might “Alternatively with canonical tag” displays. There you can also find out if Google has chosen a different Canonical than the one you specified — a clear signal that there is a need for action somewhere. With the URL check function, you can see for a specific page which URL Google regards as canonical. A quick look at the GSC also reveals errors such as duplicate canonicals, ignored canonicals, or pages that are mistakenly marked as duplicates. Tip: Check back regularly — a few minutes can provide a lot of insight.
Screaming Frog & other crawlers: If you want to dive deeper or have a big website, website crawlers like Screaming Frog SEO Spider invaluable. With Screaming Frog, you can crawl your website and have all Canonical tags output page by page. For example, you'll discover pages without a canonical, pages whose canonical points into space, or cases where canonicals point to each other (chain formation). You can also check whether two different pages are accidentally canonicalising each other somewhere (this also happens and causes confusion). Screaming Frog also provides reports, such as a list of all canonical links and their destinations — ideal for checking consistency.
Browser tools and plugins: Your browser is often enough to quickly check individual pages. With right click “View page source code” (or in Chrome better via Inspect an item<link rel="canonical">to see rendered results if JS manipulates the canonical), you can search for it in the HTML. There are also handy SEO browser extensions (for Chrome, e.g. “SEO Meta in 1 Click” or “Ayima Redirect Path”), which show you at the push of a button whether a Canonical is available and where it is pointing. This allows you to keep an eye on it whenever you browse your website.
Other monitoring tools: Many comprehensive SEO tools (such as Semrush Site Audit, Ahrefs, Sitebulb, etc.) have modules to detect duplicate content and also check canonical tags. Log file analyses can also be informative: If Google crawls certain URLs frequently despite Canonical, it is worthwhile to check whether the Canonical integration is correct.
In summary: With the right tools, you can keep track of things and ensure that your canonical tags work the way you want them to. If in doubt, it may be worthwhile to have an SEO expert look over it — false canonicals may cost you visible traffic, while correct canonicals ensure clean indexing and full SEO power.
Canonical tags can be used not only within the page, but also strategically on a larger scale. Two scenarios stand out: cross-domain canonicals and use for website changes or Relaunches. Let's have a look at what it's all about:
Cross-domain canonical: Canonical tags usually point to URLs from the same website. However, in theory, you can also rely on a other domain show — this is called cross-domain canonical. When does that make sense? Imagine a company running two websites with very similar content. For example, an old shop and, in parallel, a new shop on another domain, which is gradually being expanded. You now want to consciously steer Google to the new shop without immediately shutting down the old one. Here, the old shop on important pages can receive a canonical tag for the corresponding page on the new domain. This signals to Google:”Please prefer the new domain for this product/category“. This tactic can help to build up the rankings of the new domain more quickly, as Google does not regard the content as double competition, but regards the new shop as decisive. Important: Both pages must be almost identical in content, otherwise Google may ignore the canonicals. Cross-domain Canonical can also be used for content syndication — e.g. when a blog post is mirrored on a partner site, the partner site could link to the original article via Canonical to avoid duplicate content and attribute the ranking to the original.
SEO during relaunches: During domain changes or major relaunches, 301 redirects are usually used to redirect old URLs to new URLs — this is the cleanest way. However, there are cases where canonicals are used temporarily. For example: A company wants to gradually migrate content to a new domain, but not immediately redirect it because the old website should still be live. A cross-domain canonical (as described above) is then a Interim solution. However, such a state of affairs should not be maintained forever. In the long term, direct redirects or shutting down the duplicate website are the better option to establish consistency. Nevertheless, in strategic SEO planning, a canonical can serve as a gentle clue in a direction where hard redirects are not (yet) possible.
Link juice and ranking signals: One often discussed aspect is how a canonical tag transmits ranking signals. Background: If page A and page B are identical and A links to B via canonical, then backlink signals are usually also consolidated — in other words, all external links on A ultimately benefit B (similar to a 301 redirect). Google itself has introduced Canonicals as a signal to consolidate links. Older SEO posts also spoke of Canonical as a tool to share “link juice.” Currently, you can simply say: A canonical bundles the signals and prevents two sites from competing for rankings in parallel. In this respect, it indirectly strengthens the chosen canonical side. However, it does not completely replace a redirect if the goal is to finally lead all users and links to a new URL.
Be careful with different content: Canonical tags should only be set if the content is really the same or very similar. It would be strategically wrong to try to create a weaker side To steer to a stronger page in terms of content via Canonical, just to perhaps benefit from the ranking. Google recognises such games and will ignore the Canonical recommendation — or, in the worst case, rate both sides worse, as trust decreases. Example: You can't have a blog article shown on the homepage via Canonical in the hope that the homepage will then rank for everything possible. Use strategically, don't misuse!
Summarised: Canonicals are flexible helpers in the SEO toolbox. They can be used wisely to stay in control of complex setups (multiple domains, gradual relocation, duplication of content through collaborations). But always with the proviso that it remains logical for Google. If you are unsure whether a cross-domain canonical is appropriate, consult an experienced SEO. There are often several solutions (Redirect, Noindex, Canonical), and which is the best strategically depends on the individual case.
The Canonical is a small day with a big impact. Used correctly, it ensures clear conditions: Your most important pages appear in the index, while duplicate pages remain in the background. Especially in times when websites are becoming more and more extensive and technically complex, the Canonical Tag is a Must-have for every SEO manager and webmaster. However, it is not a panacea — careful implementation and regular monitoring are crucial so that Google implements the notice as desired.
At pan pan, we offer SEO consulting and digital strategy advice to help you develop an optimal SEO strategy, don't hesitate to get in touch to learn more about how we can help your brand grow in organic search.
The canonical tag (also known as “rel canonical href https”) is an HTML tag that is inserted as a link element in the header of an HTML page. It points search engines to the original URL (also known as a canonical URL), i.e. the preferred original resource of content. Website operators use Canonical to avoid duplicate content, highlight the correct version (resource) for search engines and focus their organic traffic on the relevant page.
The canonical tag is placed within the <head>section (i.e. in the header) of an HTML document. It is a link element and usually has the rel="canonical” attribute and an href attribute with the full canonical URL that starts with https (rel canonical href https). Alternatively, canonicalisation can also be carried out via the HTTP response header — useful, for example, for non-HTML documents such as PDF versions or other types of files and resources that do not allow a classic HTML tag.
A 301 redirect automatically redirects users and search engines from one page to another URL, permanently transmitting rankings and traffic. A canonical tag, on the other hand, is a link element in an HTML document that only recommends to search engines which version of a resource should be considered the “original URL.” In other words, users don't notice anything with Canonicals — traffic stays on the original page. Redirections via HTTP headers are more mandatory than canonicals; however, the latter offer more flexibility when canonicalising similar HTML pages or documents, such as PDF versions.
The choice between noindex and canonical depends on the type of duplicate content. The HTML tag noindex clearly signals to search engines not to include a resource in the index at all. The canonical tag, on the other hand, refers as a link element to the preferred, “canonical URL” or “original resource” of a similar page. For documents or content that offer little added value on their own (e.g. print versions, internal searches or comments), noindex is often suitable. Pages that are similar in content and yet important (e.g. product variants) are typically canonised to a common original URL using a canonical tag.
Yes, a canonical tag can also be used across domains by referring to an original URL on another domain (rel canonical href https). This technique is called Cross-Domain Canonical and is used, for example, when the same content or documents (e.g. PDF versions) exist on multiple domains. It is important here that the content of both HTML pages or resources is almost identical. Alternatively, you can also do the canonicalisation via the HTTP response header, especially if there is no classic HTML document.
Google regards the canonical tag (rel canonical href https) as a recommendation, not as a requirement. If Google ignores the tag, it could be because the original resource set as a canonical URL differs significantly in content from the page that links to it. Incorrect implementations in the HTML page header, conflicting tags (e.g. combination with noindex), or incorrect canonicalisation can also be reasons. Check the implementation for errors in both the HTML document and the HTTP response header to ensure that Google accepts the Canonical.
The Canonical Day (also rel=canonical ) is a small snippet of HTML code in the <head>area of a website that gives a clear recommendation to search engines which URL as preferred version a page should be viewed. In practice, it is primarily used to avoid duplicate content — i.e. duplicate or very similar content on different URLs. Why is that important? Duplicate content can confuse search engines, unnecessarily inflate indexing and, in the worst case, result in the wrong side appears in search results. Studies show that almost 30% of all content on the web is duplicate content (source: Raven Tools) — an enormous amount that underscores the need for effective solutions.
Search engines such as Google, Bing & Co. introduced the Canonical Tag back in 2009 to give website operators a tool against such duplicate content. SEO managers, marketing managers and online shop operators are often confronted with the topic in practice: Similar or identical content can quickly end up on the website in multiple versions for technical reasons. This is where the Canonical Tag comes in to provide clarity for search engines. ESR signals:”Hey Google, this is the main page — index it preferably!“. The canonical tag thus makes a significant contribution to saving crawl budget, bundling ranking signals and ensuring optimal user navigation.
Before we go into detail, you should know: The Canonical Tag is not rocket science, but an essential standard in the search engine optimisation of modern websites — especially for larger online shops or content websites. In this guide, you will learn everything you need to know in a locker-professional manner: from typical use cases and common mistakes to best practices, tools and strategic tricks. Let's get started!
In which situations is the Canonical Tag used? Whenever multiple URLs offer very similar content. Here are some typical use cases from practice (from e-commerce to B2B):
In short: Wherever the same or very similar content appears at multiple addresses, the Canonical Tag is worth its weight in gold. It protects against cannibalisation of your own content and ensures that only the most relevant version ends up in the Google index.
As useful as Canonical Day is — in practice, we unfortunately also see many SEO consultants implementation failure and misunderstandings. Here are the most common pitfalls so that you can avoid them in your project:
As you can see, the devil is in the details. Many of these mistakes are technical in nature, others are created by incorrect assumptions. Fortunately, you can avoid them all if you know about them — and that's exactly why you're reading this guide!
Now that we know what can go wrong, the question is: How do you do it right? Here are best practices for working with Canonical tags—as well as tools to help you review and monitor implementation:
Each indexable page gets a self-referencing canonical: It has been tried and tested to set a canonical tag on all important pages that points to yourself when the page should be indexed below itself. Example: the start page contains <link rel="canonical” href=”https://www.example.com/“>. Such a self-canonical creates clarity. If duplicates of this page are accidentally created at some point, Google immediately knows which URL is the right one. Modern CMS often use self-referencing canonicals by default — you should still check it.
Consistently point duplicates to main URL: In cases of duplicate content (see use cases above), a version should always be set as canonical. All other duplicate URLs point to this master version via a canonical tag. For example, for product variants, every size/color URL points to the product.html without parameters. Important: The canonical page itself links On yourself (see point above). This creates a clean canonical chain without breaks.
Use absolute URL in canonical: The href address in the canonical tag should ideally be specified as a full URL (including https://...). Relative paths could also work in theory, but there is a risk of errors. consistent use of www or non-www, Trailing Slashes etc. is also part of a consistent strategy — the canonical URL should be written exactly as the preferred index URL should look.
No canonicals on paginated pages one below the other (unless useful): With Pagination (e.g. page 2 of an article list) do not blunt canonicalise all pages on page 1 — there are other solutions for this, such as rel="prev/next”. However, this is also no longer recommended by Google. Preferably, or you can leave all pages indexable. Google recognises the paginated pages as belonging together, provided that they have an independent value. Canonical can be used here if, for example, pages 2—N have very thin content and you only want to make expli rank page 1, but that is advanced and requires caution.
Combination with hreflang: The following applies to multilingual websites: Different language versions not Merge via Canonical (unless there are 1:1 duplicates in the same language). Instead, you use hreflang to tell Google the language and country variants. Canonical is only used here if eine The language version is the preferred one and the other is really superfluous (e.g. identical English content on .com and.co.uk — here you could canonicalise one on top of the other, although it would be cleaner to take one version offline).
Conduct audits regularly: Websites are alive — updates, new features or team changes can subconsciously undermine the Canonical strategy. Therefore, plan regular SEO audits one to check canonical tags. Especially during relaunches, attention should be paid to correct canonicals.
Google Search Console (GSC): The most important tool for verifying Canonicals is the free Google Search Console. In the GSC, you can go to “Indexing” resp “Pages” See which URLs have been indexed and whether Google might “Alternatively with canonical tag” displays. There you can also find out if Google has chosen a different Canonical than the one you specified — a clear signal that there is a need for action somewhere. With the URL check function, you can see for a specific page which URL Google regards as canonical. A quick look at the GSC also reveals errors such as duplicate canonicals, ignored canonicals, or pages that are mistakenly marked as duplicates. Tip: Check back regularly — a few minutes can provide a lot of insight.
Screaming Frog & other crawlers: If you want to dive deeper or have a big website, website crawlers like Screaming Frog SEO Spider invaluable. With Screaming Frog, you can crawl your website and have all Canonical tags output page by page. For example, you'll discover pages without a canonical, pages whose canonical points into space, or cases where canonicals point to each other (chain formation). You can also check whether two different pages are accidentally canonicalising each other somewhere (this also happens and causes confusion). Screaming Frog also provides reports, such as a list of all canonical links and their destinations — ideal for checking consistency.
Browser tools and plugins: Your browser is often enough to quickly check individual pages. With right click “View page source code” (or in Chrome better via Inspect an item<link rel="canonical">to see rendered results if JS manipulates the canonical), you can search for it in the HTML. There are also handy SEO browser extensions (for Chrome, e.g. “SEO Meta in 1 Click” or “Ayima Redirect Path”), which show you at the push of a button whether a Canonical is available and where it is pointing. This allows you to keep an eye on it whenever you browse your website.
Other monitoring tools: Many comprehensive SEO tools (such as Semrush Site Audit, Ahrefs, Sitebulb, etc.) have modules to detect duplicate content and also check canonical tags. Log file analyses can also be informative: If Google crawls certain URLs frequently despite Canonical, it is worthwhile to check whether the Canonical integration is correct.
In summary: With the right tools, you can keep track of things and ensure that your canonical tags work the way you want them to. If in doubt, it may be worthwhile to have an SEO expert look over it — false canonicals may cost you visible traffic, while correct canonicals ensure clean indexing and full SEO power.
Canonical tags can be used not only within the page, but also strategically on a larger scale. Two scenarios stand out: cross-domain canonicals and use for website changes or Relaunches. Let's have a look at what it's all about:
Cross-domain canonical: Canonical tags usually point to URLs from the same website. However, in theory, you can also rely on a other domain show — this is called cross-domain canonical. When does that make sense? Imagine a company running two websites with very similar content. For example, an old shop and, in parallel, a new shop on another domain, which is gradually being expanded. You now want to consciously steer Google to the new shop without immediately shutting down the old one. Here, the old shop on important pages can receive a canonical tag for the corresponding page on the new domain. This signals to Google:”Please prefer the new domain for this product/category“. This tactic can help to build up the rankings of the new domain more quickly, as Google does not regard the content as double competition, but regards the new shop as decisive. Important: Both pages must be almost identical in content, otherwise Google may ignore the canonicals. Cross-domain Canonical can also be used for content syndication — e.g. when a blog post is mirrored on a partner site, the partner site could link to the original article via Canonical to avoid duplicate content and attribute the ranking to the original.
SEO during relaunches: During domain changes or major relaunches, 301 redirects are usually used to redirect old URLs to new URLs — this is the cleanest way. However, there are cases where canonicals are used temporarily. For example: A company wants to gradually migrate content to a new domain, but not immediately redirect it because the old website should still be live. A cross-domain canonical (as described above) is then a Interim solution. However, such a state of affairs should not be maintained forever. In the long term, direct redirects or shutting down the duplicate website are the better option to establish consistency. Nevertheless, in strategic SEO planning, a canonical can serve as a gentle clue in a direction where hard redirects are not (yet) possible.
Link juice and ranking signals: One often discussed aspect is how a canonical tag transmits ranking signals. Background: If page A and page B are identical and A links to B via canonical, then backlink signals are usually also consolidated — in other words, all external links on A ultimately benefit B (similar to a 301 redirect). Google itself has introduced Canonicals as a signal to consolidate links. Older SEO posts also spoke of Canonical as a tool to share “link juice.” Currently, you can simply say: A canonical bundles the signals and prevents two sites from competing for rankings in parallel. In this respect, it indirectly strengthens the chosen canonical side. However, it does not completely replace a redirect if the goal is to finally lead all users and links to a new URL.
Be careful with different content: Canonical tags should only be set if the content is really the same or very similar. It would be strategically wrong to try to create a weaker side To steer to a stronger page in terms of content via Canonical, just to perhaps benefit from the ranking. Google recognises such games and will ignore the Canonical recommendation — or, in the worst case, rate both sides worse, as trust decreases. Example: You can't have a blog article shown on the homepage via Canonical in the hope that the homepage will then rank for everything possible. Use strategically, don't misuse!
Summarised: Canonicals are flexible helpers in the SEO toolbox. They can be used wisely to stay in control of complex setups (multiple domains, gradual relocation, duplication of content through collaborations). But always with the proviso that it remains logical for Google. If you are unsure whether a cross-domain canonical is appropriate, consult an experienced SEO. There are often several solutions (Redirect, Noindex, Canonical), and which is the best strategically depends on the individual case.
The Canonical is a small day with a big impact. Used correctly, it ensures clear conditions: Your most important pages appear in the index, while duplicate pages remain in the background. Especially in times when websites are becoming more and more extensive and technically complex, the Canonical Tag is a Must-have for every SEO manager and webmaster. However, it is not a panacea — careful implementation and regular monitoring are crucial so that Google implements the notice as desired.
At pan pan, we offer SEO consulting and digital strategy advice to help you develop an optimal SEO strategy, don't hesitate to get in touch to learn more about how we can help your brand grow in organic search.
The canonical tag (also known as “rel canonical href https”) is an HTML tag that is inserted as a link element in the header of an HTML page. It points search engines to the original URL (also known as a canonical URL), i.e. the preferred original resource of content. Website operators use Canonical to avoid duplicate content, highlight the correct version (resource) for search engines and focus their organic traffic on the relevant page.
The canonical tag is placed within the <head>section (i.e. in the header) of an HTML document. It is a link element and usually has the rel="canonical” attribute and an href attribute with the full canonical URL that starts with https (rel canonical href https). Alternatively, canonicalisation can also be carried out via the HTTP response header — useful, for example, for non-HTML documents such as PDF versions or other types of files and resources that do not allow a classic HTML tag.
A 301 redirect automatically redirects users and search engines from one page to another URL, permanently transmitting rankings and traffic. A canonical tag, on the other hand, is a link element in an HTML document that only recommends to search engines which version of a resource should be considered the “original URL.” In other words, users don't notice anything with Canonicals — traffic stays on the original page. Redirections via HTTP headers are more mandatory than canonicals; however, the latter offer more flexibility when canonicalising similar HTML pages or documents, such as PDF versions.
The choice between noindex and canonical depends on the type of duplicate content. The HTML tag noindex clearly signals to search engines not to include a resource in the index at all. The canonical tag, on the other hand, refers as a link element to the preferred, “canonical URL” or “original resource” of a similar page. For documents or content that offer little added value on their own (e.g. print versions, internal searches or comments), noindex is often suitable. Pages that are similar in content and yet important (e.g. product variants) are typically canonised to a common original URL using a canonical tag.
Yes, a canonical tag can also be used across domains by referring to an original URL on another domain (rel canonical href https). This technique is called Cross-Domain Canonical and is used, for example, when the same content or documents (e.g. PDF versions) exist on multiple domains. It is important here that the content of both HTML pages or resources is almost identical. Alternatively, you can also do the canonicalisation via the HTTP response header, especially if there is no classic HTML document.
Google regards the canonical tag (rel canonical href https) as a recommendation, not as a requirement. If Google ignores the tag, it could be because the original resource set as a canonical URL differs significantly in content from the page that links to it. Incorrect implementations in the HTML page header, conflicting tags (e.g. combination with noindex), or incorrect canonicalisation can also be reasons. Check the implementation for errors in both the HTML document and the HTTP response header to ensure that Google accepts the Canonical.
