{"id":28754,"date":"2019-07-18T10:16:39","date_gmt":"2019-07-18T18:16:39","guid":{"rendered":"https:\/\/ahrefs.com\/blog\/?p=28754"},"modified":"2025-12-18T08:50:11","modified_gmt":"2025-12-18T13:50:11","slug":"canonical-tags","status":"publish","type":"post","link":"https:\/\/ahrefs.com\/blog\/canonical-tags\/","title":{"rendered":"Canonical Tags Explained: Why They Matter For&nbsp;SEO"},"content":{"rendered":"\n<div class=\"intro-txt\">Canonical tags help prevent duplicate content issues that can hurt your&nbsp;SEO.&nbsp;<\/div>\n\n\n\n<p>Here\u2019s how they work and when to use&nbsp;them.<\/p>\n\n\n\n<div class=\"intro-tok\" id=\"intro_tok\" style=\"display:none;\"><div class=\"intro-title\">Contents<\/div><a href=\"#\" class=\"expand-dots\"><span><\/span><span><\/span><span><\/span><\/a><\/div>\n\n\n\n<div class=\"post-nav-link clearfix\" id=\"section1\"><a class=\"subhead-anchor\" data-tip=\"tooltip__copielink\" rel=\"#section1\"><svg width=\"19\" height=\"19\" viewBox=\"0 0 14 14\" style><g fill=\"none\" fill-rule=\"evenodd\"><path d=\"M0 0h14v14H0z\" \/><path d=\"M7.45 9.887l-1.62 1.621c-.92.92-2.418.92-3.338 0a2.364 2.364 0 0 1 0-3.339l1.62-1.62-1.273-1.272-1.62 1.62a4.161 4.161 0 1 0 5.885 5.884l1.62-1.62L7.45 9.886zM5.527 5.135L7.17 3.492c.92-.92 2.418-.92 3.339 0 .92.92.92 2.418 0 3.339L8.866 8.473l1.272 1.273 1.644-1.643A4.161 4.161 0 1 0 5.897 2.22L4.254 3.863l1.272 1.272zm-.66 3.998a.749.749 0 0 1 0-1.06l2.208-2.206a.749.749 0 1 1 1.06 1.06L5.928 9.133a.75.75 0 0 1-1.061 0z\" style \/><\/g><\/svg><\/a><div class=\"link-text\" data-anchor=\"What is a canonical tag?\" data-section=\"what-is-a-canonical-tag\">\n\n\n\n<h2 class=\"wp-block-heading\"><a id=\"post-181737-_9tk86owi8akr\"><\/a>What is a canonical tag?<\/h2>\n\n\n\n<\/div><\/div>\n\n\n\n<p>A canonical tag (rel=\u201ccanonical\u201d) is a snippet of HTML code that tells search engines which page version is the main one when there are similar or duplicate URLs. This helps ensure only the main version is indexed.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"900\" height=\"674\" src=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-1.png\" alt=\"How canonical tags work\" class=\"wp-image-181738\" srcset=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-1.png 900w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-1-568x425.png 568w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-1-768x575.png 768w\" sizes=\"auto, (max-width: 900px) 100vw, 900px\"><\/figure>\n\n\n\n<p>Here\u2019s an example canonical tag:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>&lt;link rel=\"canonical\" href=\"https:\/\/example.com\/\" \/&gt;<\/code><\/pre>\n\n\n\n<p>The URL you specify is the master version of the page that you want indexed.<\/p>\n\n\n\n<div class=\"post-nav-link clearfix\" id=\"section1\"><a class=\"subhead-anchor\" data-tip=\"tooltip__copielink\" rel=\"#section1\"><svg width=\"19\" height=\"19\" viewBox=\"0 0 14 14\" style><g fill=\"none\" fill-rule=\"evenodd\"><path d=\"M0 0h14v14H0z\" \/><path d=\"M7.45 9.887l-1.62 1.621c-.92.92-2.418.92-3.338 0a2.364 2.364 0 0 1 0-3.339l1.62-1.62-1.273-1.272-1.62 1.62a4.161 4.161 0 1 0 5.885 5.884l1.62-1.62L7.45 9.886zM5.527 5.135L7.17 3.492c.92-.92 2.418-.92 3.339 0 .92.92.92 2.418 0 3.339L8.866 8.473l1.272 1.273 1.644-1.643A4.161 4.161 0 1 0 5.897 2.22L4.254 3.863l1.272 1.272zm-.66 3.998a.749.749 0 0 1 0-1.06l2.208-2.206a.749.749 0 1 1 1.06 1.06L5.928 9.133a.75.75 0 0 1-1.061 0z\" style \/><\/g><\/svg><\/a><div class=\"link-text\" data-anchor=\"When should you use canonical tags, and why are they so important for SEO?\" data-section=\"when-to-use-canonical-tags\">\n\n\n\n<h2 class=\"wp-block-heading\"><a id=\"post-181737-_gnie5ry45z2s\"><\/a>When should you use canonical tags, and why are they so important for&nbsp;SEO?<\/h2>\n\n\n\n<\/div><\/div>\n\n\n\n<p>You should use canonical tags whenever you have the same or similar content available at multiple URLs.<\/p>\n\n\n\n<p>Here are just a few of many reasons why this can happen:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>You have duplicate content at URLs with and without trailing slashes <\/strong>(e.g. example.com\/ and example.com)<\/li>\n\n\n\n<li><strong>You have duplicate content at desktop and mobile versions of pages (<\/strong>e.g., example.com and m.example.com)<\/li>\n\n\n\n<li><strong>You have duplicate content at parameterized versions of URLs <\/strong>(e.g., example.com and example?tracking-code)<\/li>\n<\/ul>\n\n\n\n<div class=\"sidenote\"><div class=\"sidenote-title\">Sidenote.<\/div> If you\u2019re syndicating or republishing content on other sites, this is another time to use canonical tags. If you don\u2019t, there\u2019s a risk of Google treating the syndicated or republished version of the content as the original and ranking it ahead of your site in the search results.<\/div>\n\n\n\n<p>For example, say you have an ecommerce store selling widgets. You might have a category page listing all your blue widgets at this URL: <code>example.com\/widgets\/blue\/<\/code>. But the exact same content might be accessible at an ugly URL like this when visitors apply product filters: <code>example.com\/widgets?color=blue<\/code><\/p>\n\n\n\n<p>Unless you specify the canonical, the \u201cwrong\u201d version of the URL might get indexed and appear in search results.<\/p>\n\n\n\n<p>Canonical tags also help ensure that ranking signals like links consolidate to one page. This is important because links are a confirmed <a href=\"https:\/\/ahrefs.com\/blog\/google-ranking-factors\/\">Google ranking factor<\/a>, and there\u2019s a strong correlation between links and traffic.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1678\" height=\"1658\" src=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-2.png\" alt=\"Our research shows that there's a clear correlation between backlinks and search traffic\" class=\"wp-image-181739\" srcset=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-2.png 1678w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-2-430x425.png 430w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-2-768x759.png 768w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-2-1536x1518.png 1536w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-2-120x120.png 120w\" sizes=\"auto, (max-width: 1678px) 100vw, 1678px\"><\/figure>\n\n\n\n<p>Too much duplicate content can also burn \u201ccrawl budget,\u201d which is where Google wastes its resources crawling duplicate versions of content instead of new pages you actually want indexed. Sure, it will probably figure out eventually that it shouldn\u2019t crawl pages regularly, but it has to crawl them initially to before it can do that\u2014which is what wastes crawl budget.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"900\" height=\"557\" src=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-3.png\" alt=\"Google is smart and will stop recrawling duplicate content, but it has to crawl it initially to figure that out which wastes crawl budget\" class=\"wp-image-181740\" srcset=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-3.png 900w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-3-680x421.png 680w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-3-768x475.png 768w\" sizes=\"auto, (max-width: 900px) 100vw, 900px\"><\/figure>\n\n\n\n<div class=\"post-nav-link clearfix\" id=\"section1\"><a class=\"subhead-anchor\" data-tip=\"tooltip__copielink\" rel=\"#section1\"><svg width=\"19\" height=\"19\" viewBox=\"0 0 14 14\" style><g fill=\"none\" fill-rule=\"evenodd\"><path d=\"M0 0h14v14H0z\" \/><path d=\"M7.45 9.887l-1.62 1.621c-.92.92-2.418.92-3.338 0a2.364 2.364 0 0 1 0-3.339l1.62-1.62-1.273-1.272-1.62 1.62a4.161 4.161 0 1 0 5.885 5.884l1.62-1.62L7.45 9.886zM5.527 5.135L7.17 3.492c.92-.92 2.418-.92 3.339 0 .92.92.92 2.418 0 3.339L8.866 8.473l1.272 1.273 1.644-1.643A4.161 4.161 0 1 0 5.897 2.22L4.254 3.863l1.272 1.272zm-.66 3.998a.749.749 0 0 1 0-1.06l2.208-2.206a.749.749 0 1 1 1.06 1.06L5.928 9.133a.75.75 0 0 1-1.061 0z\" style \/><\/g><\/svg><\/a><div class=\"link-text\" data-anchor=\"How to add canonical tags to your site\" data-section=\"how-to-add-canonical-tags\">\n\n\n\n<h2 class=\"wp-block-heading\"><a id=\"post-181737-_912msqop3hzf\"><\/a>How to add canonical tags to your&nbsp;site<\/h2>\n\n\n\n<\/div><\/div>\n\n\n\n<p>You can do this manually by adding <code>&lt;link rel=\"canonical\" href=\"https:\/\/example.com\"\/&gt;<\/code> to the <code>&lt;head&gt;<\/code> section of your page\u2019s code, but hardly anyone does that because it\u2019s too much hassle. It\u2019s usually way easier to do it through your website platform.<\/p>\n\n\n\n<p>However you choose to do it, make sure to follow these golden rules:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Use absolute URLs. <\/strong>Google <a href=\"https:\/\/developers.google.com\/search\/docs\/crawling-indexing\/consolidate-duplicate-urls\">says<\/a> not to use relative URLs (e.g., <code>\/sample-page\/<\/code>), even though they\u2019re supported. This means you should specify full absolute URLs in canonical tags (e.g., <code>https:\/\/example.com\/sample-page\/<\/code>).<\/li>\n\n\n\n<li><strong>Use the correct domain.<\/strong> If you switched over to SSL (you should have by now!), make sure that you don\u2019t declare any non-SSL (i.e., HTTP) URLs in your canonical tags. Doing so can lead to confusion on Google\u2019s part and unexpected results.<\/li>\n\n\n\n<li><strong>Specify only one canonical per page.<\/strong> Google will <a href=\"https:\/\/developers.google.com\/search\/blog\/2013\/04\/5-common-mistakes-with-relcanonical\">ignore<\/a> all declared canonicals if you declare more than&nbsp;one.<\/li>\n<\/ol>\n\n\n\n<p>Let\u2019s take a look at the process for a few popular platforms.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_d93o8c7dqi14\"><\/a>Setting canonical tags in WordPress<\/h3>\n\n\n\n<p>Install <a href=\"https:\/\/wordpress.org\/plugins\/wordpress-seo\/\">Yoast SEO<\/a>, then scroll to the \u201cAdvanced\u201d section on a page or post where you\u2019ll see an option to specify a canonical.<\/p>\n\n\n\n<figure class=\"wp-block-image is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1192\" height=\"812\" src=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-4.png\" alt=\"Adding canonical tags to WordPress\" class=\"wp-image-181741\" style=\"width:555px;height:auto\" srcset=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-4.png 1192w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-4-624x425.png 624w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-4-768x523.png 768w\" sizes=\"auto, (max-width: 1192px) 100vw, 1192px\"><\/figure>\n\n\n\n<p><\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_kr067l1qfutd\"><\/a>Setting canonical tags in&nbsp;Wix<\/h3>\n\n\n\n<p>Follow <a href=\"https:\/\/support.wix.com\/en\/article\/changing-the-canonical-tags-for-your-sites-pages\">their step-by-step guide<\/a>. It\u2019s a bit convoluted compared to WordPress, but it\u2019s still possible.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_ga5wtfeeo65z\"><\/a>Setting canonical tags in Shopify<\/h3>\n\n\n\n<p>Shopify handles canonicalization fairly well out of the box. Does that mean it\u2019s always perfect? No. But most small and medium sized stores probably won\u2019t need to add canonical tags manually. I\u2019d recommend getting a developer\u2019s help if you need to, as you\u2019ll need to edit your theme\u2019s code (.liquid files) directly.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_j0aj1r5dw33o\"><\/a>Setting canonical tags in Squarespace<\/h3>\n\n\n\n<p>Go to the advanced settings of your page and you can inject canonical tags into the header.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1546\" height=\"862\" src=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-5.png\" alt=\"Adding canonical tags to Squarespace\" class=\"wp-image-181742\" srcset=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-5.png 1546w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-5-680x379.png 680w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-5-768x428.png 768w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-5-1536x856.png 1536w\" sizes=\"auto, (max-width: 1546px) 100vw, 1546px\"><\/figure>\n\n\n\n<div class=\"post-nav-link clearfix\" id=\"section1\"><a class=\"subhead-anchor\" data-tip=\"tooltip__copielink\" rel=\"#section1\"><svg width=\"19\" height=\"19\" viewBox=\"0 0 14 14\" style><g fill=\"none\" fill-rule=\"evenodd\"><path d=\"M0 0h14v14H0z\" \/><path d=\"M7.45 9.887l-1.62 1.621c-.92.92-2.418.92-3.338 0a2.364 2.364 0 0 1 0-3.339l1.62-1.62-1.273-1.272-1.62 1.62a4.161 4.161 0 1 0 5.885 5.884l1.62-1.62L7.45 9.886zM5.527 5.135L7.17 3.492c.92-.92 2.418-.92 3.339 0 .92.92.92 2.418 0 3.339L8.866 8.473l1.272 1.273 1.644-1.643A4.161 4.161 0 1 0 5.897 2.22L4.254 3.863l1.272 1.272zm-.66 3.998a.749.749 0 0 1 0-1.06l2.208-2.206a.749.749 0 1 1 1.06 1.06L5.928 9.133a.75.75 0 0 1-1.061 0z\" style \/><\/g><\/svg><\/a><div class=\"link-text\" data-anchor=\"Other ways to declare canonical URLs\" data-section=\"other-ways-to-declare-canonical-urls\">\n\n\n\n<h2 class=\"wp-block-heading\"><a id=\"post-181737-_6ql3byfdptvg\"><\/a>Other ways to declare canonical URLs<\/h2>\n\n\n\n<\/div><\/div>\n\n\n\n<p>Canonical tags are not the only way to declare a page\u2019s canonical. You can use three other methods:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Redirect<\/li>\n\n\n\n<li>rel=\u201ccanonical\u201d in HTTP header<\/li>\n\n\n\n<li>Sitemap<\/li>\n<\/ol>\n\n\n\n<div class=\"sidenote\"><div class=\"sidenote-title\">Sidenote.<\/div> If none of these are used, Google will rely on other signals like <a href=\"https:\/\/ahrefs.com\/blog\/hreflang-tags\/\">hreflang<\/a>, <a href=\"https:\/\/ahrefs.com\/blog\/internal-links-for-seo\/\">internal links<\/a>, and URL length to choose a canonical for you if it believes you have duplicate content.<\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_mp7y7onp59lx\"><\/a>Redirects<\/h3>\n\n\n\n<p>Google says to use this only when deprecating a duplicate page because it redirects Googlebot (and visitors) to a different URL. This is a particularly useful option for duplicate content caused by both HTTP and HTTPS pages being accessible.<\/p>\n\n\n\n<div class=\"further-reading\"><div class=\"reading-title\">Further reading<\/div><div class=\"reading-content\">\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/ahrefs.com\/blog\/301-redirects\/\">301 Redirects Explained: How They Impact SEO<\/a><\/li>\n<\/ul>\n\n\n\n<\/div><\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_mr8ild2dxhyr\"><\/a>rel=\u201ccanonical\u201d in HTTP header<\/h3>\n\n\n\n<p>For documents like PDFs, there\u2019s no way to place canonical tags in the page header because there is no page &lt;head&gt; section. In such cases, you\u2019ll need to use HTTP headers to set canonicals.<\/p>\n\n\n\n<p>Here\u2019s what that might look like for a PDF version of this blog&nbsp;post:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">HTTP\/1.1 200 OK<br><br>Content-Type: application\/pdf<br><br>Link: &lt;https:\/\/ahrefs.com\/blog\/canonical-tags\/&gt;; rel=\"canonical\"<\/pre>\n\n\n\n<p>You can also use a canonical in HTTP headers on standard webpages.<\/p>\n\n\n\n<div class=\"further-reading\"><div class=\"reading-title\">Further reading<\/div><div class=\"reading-content\">\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/geoffkenyon.com\/how-to-add-canonical-tag-http-headers\/\">How to Add the Canonical Tag to HTTP Headers<\/a><\/li>\n<\/ul>\n\n\n\n<\/div><\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_ktcarnd8d48i\"><\/a>Sitemap<\/h3>\n\n\n\n<p>Only canonical URLs should be listed in your sitemap, although Google says that doing so is <a href=\"https:\/\/developers.google.com\/search\/docs\/crawling-indexing\/consolidate-duplicate-urls\">a weak canonicalization signal<\/a>.<\/p>\n\n\n\n<div class=\"sidenote\"><div class=\"sidenote-title\">Sidenote.<\/div> Links, both internal and external, are another canonicalization signal as John Mueller mentions in <a href=\"https:\/\/www.youtube-nocookie.com\/embed\/8j_hxBw5B4E\">this video<\/a>.<\/div>\n\n\n\n<div class=\"post-nav-link clearfix\" id=\"section1\"><a class=\"subhead-anchor\" data-tip=\"tooltip__copielink\" rel=\"#section1\"><svg width=\"19\" height=\"19\" viewBox=\"0 0 14 14\" style><g fill=\"none\" fill-rule=\"evenodd\"><path d=\"M0 0h14v14H0z\" \/><path d=\"M7.45 9.887l-1.62 1.621c-.92.92-2.418.92-3.338 0a2.364 2.364 0 0 1 0-3.339l1.62-1.62-1.273-1.272-1.62 1.62a4.161 4.161 0 1 0 5.885 5.884l1.62-1.62L7.45 9.886zM5.527 5.135L7.17 3.492c.92-.92 2.418-.92 3.339 0 .92.92.92 2.418 0 3.339L8.866 8.473l1.272 1.273 1.644-1.643A4.161 4.161 0 1 0 5.897 2.22L4.254 3.863l1.272 1.272zm-.66 3.998a.749.749 0 0 1 0-1.06l2.208-2.206a.749.749 0 1 1 1.06 1.06L5.928 9.133a.75.75 0 0 1-1.061 0z\" style \/><\/g><\/svg><\/a><div class=\"link-text\" data-anchor=\"Common canonicalization mistakes and best practices\" data-section=\"canonicalization-mistakes-and-best-practices\">\n\n\n\n<h2 class=\"wp-block-heading\"><a id=\"post-181737-_qxefnlcvjtta\"><\/a>Common canonicalization mistakes and best practices<\/h2>\n\n\n\n<\/div><\/div>\n\n\n\n<p>Canonicalization can be complex. Because of this, there are a lot of misunderstandings and misconceptions about how to canonicalize properly.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_i97znwcz9wgv\"><\/a>Mistake #1: Blocking the canonicalized URL via robots.txt<\/h3>\n\n\n\n<p>Blocking a URL in <a href=\"https:\/\/ahrefs.com\/blog\/robots-txt\/\">robots.txt<\/a> prevents Google from crawling it, meaning that it\u2019s unable to see any canonical tags on that page. That, in turn, prevents it from transferring any \u201clink equity\u201d from the non-canonical to the canonical.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_3gwu9s7flpn7\"><\/a>Mistake #2: Setting the canonicalized URL to noindex<\/h3>\n\n\n\n<p>Never mix noindex and rel=canonical. They\u2019re contradictory instructions.<\/p>\n\n\n\n<p>John Mueller <a href=\"https:\/\/www.reddit.com\/r\/TechSEO\/comments\/8yahdr\/2_questions_about_the_canonical_tag\/e2dey9i\/?context=1\">said<\/a> on Reddit that Google will generally prioritize the canonical tag over the noindex tag, but it\u2019s not a guarantee. Google\u2019s official documentation says that noindex will completely remove the page from search. That may be the desired end result, but other canonicalization methods should have the same effect without the potential downsides (e.g., Google not being able to consolidate \u201clink equity\u201d).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_xna39jik807i\"><\/a>Mistake #3: Setting a 4XX HTTP status code for the canonicalized URL<\/h3>\n\n\n\n<p>Setting a 4XX HTTP status code for a canonicalized URL has the same effect as using the noindex tag: Google will be unable to see the canonical tag and, therefore, can\u2019t transfer \u201clink equity\u201d to the canonical version.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_9a3lbiw1anha\"><\/a>Mistake #4: Canonicalizing all paginated pages to the root&nbsp;page<\/h3>\n\n\n\n<p>Google <a href=\"https:\/\/developers.google.com\/search\/docs\/specialty\/ecommerce\/pagination-and-incremental-page-loading\">says<\/a> not to canonicalize paginated pages to the first in the series.<\/p>\n\n\n\n<div class=\"sidenote\"><div class=\"sidenote-title\">Sidenote.<\/div> You should also use rel=prev\/next tags for pagination. These are <a href=\"https:\/\/twitter.com\/JohnMu\/status\/1108717486424363009\">no longer used by Google<\/a>, but <a href=\"https:\/\/twitter.com\/CoperniX\/status\/1108799603963514880\">Bing still uses them<\/a>.<\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_sig9fpr5elws\"><\/a>Mistake #5: Not using canonical tags with hreflang<\/h3>\n\n\n\n<p><a href=\"https:\/\/ahrefs.com\/blog\/hreflang-tags\/\">Hreflang tags<\/a> are used to specify the language and geographical targeting of a webpage.<\/p>\n\n\n\n<p>Google <a href=\"https:\/\/support.google.com\/webmasters\/answer\/139066?hl=en\">states<\/a> that when using hreflang, you should \u201cspecify a canonical page in the same language, or the best possible substitute language if a canonical doesn\u2019t exist for the same language.\u201d<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_jjgj673tuey2\"><\/a>Mistake #6: Having multiple rel=canonical tags<\/h3>\n\n\n\n<p>Having multiple rel=canonical tags will cause them to likely be ignored by Google. In many cases this happens because tags are inserted into a system at different points such as by the CMS, the theme, and plugin(s). This is why many plugins have an overwrite option meant to make sure that they are the only source for canonical tags.<\/p>\n\n\n\n<p>Another area where this might be a problem is with canonicals added with JavaScript. If you have no canonical URL specified in the HTML response and then add a rel=canonical tag with JavaScript then it should be respected when Google renders the page. However, if you have a canonical specified in HTML and swap the preferred version with JavaScript, you are sending mixed signals to Google.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_gu00qvjerx0v\"><\/a>Mistake #7: Rel=canonical in the &lt;body&gt;<\/h3>\n\n\n\n<p>Rel=canonical should only appear in the &lt;head&gt; of a document. A canonical tag in the &lt;body&gt; section of a page will be ignored.<\/p>\n\n\n\n<p>Where this can become a problem is with the parsing of a document. While the source code of a page may have the rel=canonical tag in the correct location, when the page is actually constructed in a browser or rendered by a search engine, many different things such as unclosed tags, JavaScript injected, or &lt;iframes&gt; in the &lt;head&gt; section can cause the &lt;head&gt; to end prematurely while rendering. In these cases a canonical tag may be accidentally thrown into the &lt;body&gt; of a rendered page where it will not be respected.<\/p>\n\n\n\n<div class=\"post-nav-link clearfix\" id=\"section1\"><a class=\"subhead-anchor\" data-tip=\"tooltip__copielink\" rel=\"#section1\"><svg width=\"19\" height=\"19\" viewBox=\"0 0 14 14\" style><g fill=\"none\" fill-rule=\"evenodd\"><path d=\"M0 0h14v14H0z\" \/><path d=\"M7.45 9.887l-1.62 1.621c-.92.92-2.418.92-3.338 0a2.364 2.364 0 0 1 0-3.339l1.62-1.62-1.273-1.272-1.62 1.62a4.161 4.161 0 1 0 5.885 5.884l1.62-1.62L7.45 9.886zM5.527 5.135L7.17 3.492c.92-.92 2.418-.92 3.339 0 .92.92.92 2.418 0 3.339L8.866 8.473l1.272 1.273 1.644-1.643A4.161 4.161 0 1 0 5.897 2.22L4.254 3.863l1.272 1.272zm-.66 3.998a.749.749 0 0 1 0-1.06l2.208-2.206a.749.749 0 1 1 1.06 1.06L5.928 9.133a.75.75 0 0 1-1.061 0z\" style \/><\/g><\/svg><\/a><div class=\"link-text\" data-anchor=\"How to find and fix canonical tag issues on your site\" data-section=\"how-to-find-and-fix-canonical-tag-issues-on-your site\">\n\n\n\n<h2 class=\"wp-block-heading\"><a id=\"post-181737-_xhjcvxyqas9e\"><\/a>How to find and fix canonical tag issues on your&nbsp;site<\/h2>\n\n\n\n<\/div><\/div>\n\n\n\n<p>It\u2019s easy to make mistakes with canonicalization, so it pays to regularly audit your website for issues related to canonical tags and fix them&nbsp;ASAP.<\/p>\n\n\n\n<p>You can do this with <a href=\"https:\/\/ahrefs.com\/site-audit\">Ahrefs\u2019 Site Audit<\/a>, which you can use for free with verified websites with an <a href=\"https:\/\/ahrefs.com\/webmaster-tools\">Ahrefs Webmaster Tools (AWT)<\/a> account. It crawls your website for over 170 SEO issues, including those related to canonical tags.<\/p>\n\n\n\n<p>Here are the 14 canonical issues Site Audit may find, and how to fix&nbsp;them:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_d52njvdqdlbf\"><\/a>1. Canonical points to&nbsp;4XX<\/h3>\n\n\n\n<p>One or more pages are canonicalized to a dead (4XX)&nbsp;URL.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_313y6ap30tze\"><\/a>Why it\u2019s an&nbsp;issue<\/h4>\n\n\n\n<p>Search engines don\u2019t index 4XX pages because they don\u2019t work. As a result, they\u2019ll ignore any canonical tags pointing to such pages and often end up indexing the wrong (non-canonical) version of the&nbsp;page.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_rkw5q2wc3j4p\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Review the affected pages and replace the dead (4XX) canonical links with links to working (200) pages that you want indexed.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_ojjndddqou7p\"><\/a>2. Canonical points to&nbsp;5XX<\/h3>\n\n\n\n<p>One or more pages is canonicalized to a 5XX&nbsp;URL.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_sdwt91m30ms6\"><\/a>Why it\u2019s an&nbsp;issue<\/h4>\n\n\n\n<p>5XX HTTP status codes indicate server issues, which result in an inaccessible canonical page. Google is unlikely to index inaccessible pages, so may ignore the canonical.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_fqoedbk0bryf\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Replace any erroneous canonical URLs with valid URLs. Check for server misconfigurations if the specified canonical seems correct. Note that this may be a temporary issue if the crawl occurred when your site was down for maintenance or your site\u2019s server overloaded.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_6hzwrwn4m1rl\"><\/a>3. Canonical points to redirect<\/h3>\n\n\n\n<p>One or more pages is canonicalized to a redirected URL.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_ltg9w68xb6zn\"><\/a>Why it\u2019s an&nbsp;issue<\/h4>\n\n\n\n<p>Canonicals should always point to the most authoritative version of a page. This is not the case with redirecting URLs. As a result, search engines may misinterpret or ignore the canonical.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_ew0ppn3tl5z7\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Replace the canonical links with direct links to the most authoritative version of the page (i.e., one that returns a 200 HTTP status code and doesn\u2019t redirect).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_orjtqpl587y9\"><\/a>4. Canonical URL has no incoming internal links<\/h3>\n\n\n\n<p>One or more specified canonical URLs have no internal incoming links.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_tmxdux8d0sjy\"><\/a>Why it\u2019s an&nbsp;issue<\/h4>\n\n\n\n<p>Canonical URLs without internal links are inaccessible to website visitors. Somewhere on the site, they\u2019re being directed to a non-canonical version of the page instead.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_rc9hhakeinuk\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Replace any internal links to canonicalized pages with direct links to the canonical.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_jslqydx3wg52\"><\/a>5. Canonical URL has no incoming internal links<\/h3>\n\n\n\n<p>There are no internal links pointing to one or more declared canonical URLs.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_sb5dx7blo2h6\"><\/a>Why it\u2019s an&nbsp;issue<\/h4>\n\n\n\n<p>Because there\u2019s no way for people browsing your website to reach the canonical URL. Internal links are also a canonicalization signal for Google.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_fujtzxtc8jgy\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Check your website navigation and link architecture to make sure all canonical pages are easily accessible. You should always internally link directly to the canonical URL where possible.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_io3o2bofzx78\"><\/a>6. Duplicate pages without canonical<\/h3>\n\n\n\n<p>One or more duplicate or very similar pages exist that don\u2019t specify a canonical version.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_nhjl8di5taq4\"><\/a>Why it\u2019s an&nbsp;issue<\/h4>\n\n\n\n<p>Because no canonical is specified, Google will attempt to identify the most appropriate version to show in search results themselves. This may not be the version you want indexed.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_ychhz5w6wyts\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Review the groups of duplicates. Pick one canonical version that should be indexed in the search results. Specify this as the canonical version across all duplicates (and add a self-referencing canonical tag to the canonical version).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_b61rej6gcx3f\"><\/a>7. Hreflang to non-canonical<\/h3>\n\n\n\n<p>One or more pages specify a non-canonical URL in their hreflang annotations.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_ylijj6npbn66\"><\/a>Why it\u2019s an&nbsp;issue<\/h4>\n\n\n\n<p>Links in hreflang tags should <em>always<\/em> point to the canonical pages. Linking to a non-canonical version of a page from hreflang annotations can confuse and mislead search engines.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_kz61cpqb932x\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Replace links in the hreflang annotations of affected pages with their canonical.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_bbzhlyw4kz8r\"><\/a>8. Non-canonical page in sitemap<\/h3>\n\n\n\n<p>One or more non-canonical pages are listed in the sitemap.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_aasd0bazqpn1\"><\/a>Why it\u2019s an&nbsp;issue<\/h4>\n\n\n\n<p>Google states that you shouldn\u2019t include non-canonical URLs in your sitemap. Reason being, they see pages in sitemaps as suggested canonicals. You should only list pages that you want indexed in sitemaps.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_wren35uzquf2\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Remove non-canonical URLs from your sitemap.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_1zie8z2eu5v1\"><\/a>9. Non-canonical page specified as canonical one<\/h3>\n\n\n\n<p>One or more pages specify a canonical URL which is also canonicalized to a different page. This creates a \u201ccanonical chain\u201d where page A is canonicalized to page B, which is then canonicalized to page&nbsp;C.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"900\" height=\"579\" src=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-6.png\" alt=\"Example of a canonical chain\" class=\"wp-image-181743\" srcset=\"https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-6.png 900w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-6-661x425.png 661w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-6-260x166.png 260w, https:\/\/ahrefs.com\/blog\/wp-content\/uploads\/2024\/11\/word-image-181737-6-768x494.png 768w\" sizes=\"auto, (max-width: 900px) 100vw, 900px\"><\/figure>\n\n\n\n<p><\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_8o62geczht8n\"><\/a>Why it might be an&nbsp;issue<\/h4>\n\n\n\n<p>Canonical chains may confuse and mislead search engines. As a result, they may misinterpret or ignore the specified canonical.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_ooda45wfny4y\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Replace non-canonical links in the canonical tags of affected pages with direct links to the canonical. For example, if page A is canonicalized to page B, which is then canonicalized to page C, replace the canonical link on page A with a link to page&nbsp;C.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_1tpemqcyp24y\"><\/a>10. Open Graph URL not matching canonical<\/h3>\n\n\n\n<p>The URL specified in og:url Open Graph tag and in rel=canonical tag is mismatched.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_5wazedtj19g0\"><\/a>Why it might be an&nbsp;issue<\/h4>\n\n\n\n<p>It\u2019s not an issue for Google SEO, but a non-canonical version of a page will be shared on social networks.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_os0lo3et2jvh\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Make sure the URL specified in og:url matches the URL of the canonical page.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_gdjtk23sdzqb\"><\/a>11. Canonical from HTTPS to&nbsp;HTTP<\/h3>\n\n\n\n<p>One or more secure (HTTPS) pages specify a non-secure (HTTP) version as the canonical.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_ct7wu5xdel85\"><\/a>Why it might be worth fixing<\/h4>\n\n\n\n<p><a href=\"https:\/\/webmasters.googleblog.com\/2014\/08\/https-as-ranking-signal.html\">HTTPS is a ranking factor<\/a>, so it makes sense to specify secure versions of pages as canonical where possible.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_smry44u29k2k\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Redirect the HTTP page to the HTTPS equivalent. If that\u2019s not possible, add a rel=\u201ccanonical\u201d link from the HTTP version of the page to the HTTPS&nbsp;one.<\/p>\n\n\n\n<div class=\"sidenote\"><div class=\"sidenote-title\">Sidenote.<\/div> Google also lists implementing <a href=\"https:\/\/en.wikipedia.org\/wiki\/HTTP_Strict_Transport_Security\">HSTS<\/a> as a potential solution.<\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_h6qb2jhnt5g2\"><\/a>12. Canonical from HTTP to&nbsp;HTTPS<\/h3>\n\n\n\n<p>One or more non-secure (HTTP) pages specify a secure (HTTPS) version as the canonical.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_4eov1sp7wzrs\"><\/a>Why it might be worth fixing<\/h4>\n\n\n\n<p>HTTPS is preferred over HTTP. Having an HTTP version of a page then specifying the HTTPS version as canonical is illogical. This likely won\u2019t cause a huge issue, but it\u2019s still worth fixing if possible.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_d6uh6jgqfvoi\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Implement a 301 redirect from HTTP to HTTPS. You should also replace any internal links to the HTTP version of the page with links directly to the HTTPS version.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_y3zxriwcp7pz\"><\/a>13. Canonical URL changed<\/h3>\n\n\n\n<p>The declared canonical on one or more URLs changed since the last&nbsp;crawl.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_3mjbkjgiawic\"><\/a>Why it might be worth fixing<\/h4>\n\n\n\n<p>It could point to a mistake or issue since the last crawl. Remember that the declared canonical should be the version of the page you want Google to index and&nbsp;rank.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_dejaljnzl4m0\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Review affected pages and ensure that the changes are intentional.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><a id=\"post-181737-_3mnlojir6jov\"><\/a>14. Non-canonical page receives organic traffic<\/h3>\n\n\n\n<p>One or more non-canonical pages show up in search results and get organic search traffic (which shouldn\u2019t happen).<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_h870gvlv7hud\"><\/a>Why it might be worth fixing<\/h4>\n\n\n\n<p>Either your canonical tags are set up incorrectly or Google has chosen to ignore the specified canonical.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a id=\"post-181737-_crfsdwcuezwp\"><\/a>How to&nbsp;fix<\/h4>\n\n\n\n<p>Check that the rel=canonical tags are set up correctly on all reported pages. If that\u2019s not the issue, use the URL Inspection tool in Google Search Console to see whether they consider the specified canonical URL as canonical. If there\u2019s a mismatch, investigate why this may be the&nbsp;case.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Learn more about canonicalization<\/h2>\n\n\n\n<p>Read my colleague Patrick\u2019s <a href=\"https:\/\/ahrefs.com\/blog\/canonicalization\/\">canonicalization guide<\/a>. He goes into more detail about canonicalization signals and how to check how Google views a URL\u2019s canonical using the <a href=\"https:\/\/support.google.com\/webmasters\/answer\/9012289?hl=en\">URL Inspection tool<\/a> in Google Search Console.<\/p>\n\n\n\n<p>Got questions? Ping me on <a href=\"https:\/\/uk.linkedin.com\/in\/joshuahardwick28\">LinkedIn<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Here\u2019s how they work and when to use&nbsp;them. A canonical tag (rel=\u201ccanonical\u201d) is a snippet of HTML code that tells search engines which page version is the main one when there are similar or duplicate URLs. This helps ensure only<span class=\"ellipsis\">\u2026<\/span><\/p>\n<div class=\"read-more\">Read more \u203a<\/div>\n<p><!-- end of .read-more --><\/p>\n","protected":false},"author":114,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"wp_typography_post_enhancements_disabled":false,"footnotes":""},"categories":[329],"tags":[],"coauthors":[336],"class_list":["post-28754","post","type-post","status-publish","format-standard","hentry","category-technical-seo","odd"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.3 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Canonical Tags Explained: Why They Matter For SEO<\/title>\n<meta name=\"description\" content=\"Canonical tags help to combat duplicate content issues. They tell search engines like Google to index and rank the right pages. 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