# Canonical URL A canonical URL is the address a page names as its original. You use it to tell search engines which version to index when duplicates exist. This matters if you have parameters, sorting, or content repeated across URLs. Updated 2026-09-13 · Source: https://porteur.ai/glossary/canonical-url ## What it is and why it matters on a small site A canonical URL is set with a link rel=canonical tag or an HTTP Link header. It points to the preferred URL for that content. Small sites create duplicates without noticing: UTM parameters, uppercase paths, trailing slashes, sort and filter pages, http and https, with and without www. Each can split link equity and impressions across many URLs. A clean canonical helps one page rank and get clicks. It also reduces crawl waste and weird metrics caused by near-identical pages competing with each other. ## How to set a canonical 1. **Pick the preferred URL format** Decide on https, www or not, trailing slash or not, lowercase paths. Example: https://yourproduct.com/guides/getting-started/. 2. **Add rel=canonical on the page** In the head, link to the preferred URL. Example: /guides/getting-started?utm_source=newsletter should canonical to /guides/getting-started/. 3. **Use redirects for true duplicates** 301 redirect http to https, non-www to www, and uppercase to lowercase where needed. Canonical is not a substitute for redirects on exact duplicates. 4. **Avoid cross-page canonicals for different content** Only point to a different URL when content is the same or a close duplicate. Variants like colour or pagination often need their own URLs with self-canonicals. ```html ``` ## How to check and measure it - View source on the page and find link rel="canonical". Confirm it is absolute, matches https, host, path and trailing slash choices. - If you set it via headers, fetch the URL with curl -I or your server logs and check the Link: <...>; rel="canonical" header. - In Search Console, use URL Inspection to see the Google-selected canonical and the user-declared canonical. They should usually match. - In the Page indexing report, watch statuses. “Alternate page with proper canonical tag” means Google found a canonical to a different URL and agreed, so this URL is intentionally out of the index. It is only a problem when the canonical is wrong. - Track impressions and clicks for the canonical URL in the Performance report. Remember: impressions count when your link appears on a loaded results page, and the query table omits rare queries, so totals will differ. > Average position is the mean across impressions. One page can average 8 while appearing at 3 and at 40. CTR is clicks divided by impressions. ## What to do on a typical site 1. **Make every indexable page self-canonical** /pricing should canonical to https://yourproduct.com/pricing/. 2. **Canonical from parameter versions to clean URLs** /pricing?ref=twitter and /pricing?utm_source=newsletter should canonical to /pricing/. 3. **Handle pagination and facets with care** Let /blog/page/2/ self-canonical. For filter pages that change the list but not the detail, consider noindex or block crawling rather than canonicals to page 1. 4. **Keep canonicals consistent with redirects and hreflang** Do not canonical to a URL that 301s, 404s, is noindexed, or is disallowed in robots.txt. Hreflang alternates should each self-canonical. 5. **Audit regularly** Crawl the site after deploys. Check that templates print the right canonical on all states: with and without trailing slash, pagination, sort, and login banners. ## Common mistakes and how to fix them - Pointing every page’s canonical to the homepage. Fix: self-canonical each unique page. - Mixing http and https or www and non-www between canonical and live URL. Fix: pick one, redirect the rest, match the canonical. - Relative or malformed canonicals. Fix: use absolute URLs with the correct case and trailing slash. - Multiple canonicals from tags and headers. Fix: send only one signal, remove duplicates. - Canonical to a non-200 or blocked page. Fix: ensure the canonical URL returns 200 and is not noindex or robots.txt disallowed. - Canonical used as a soft redirect. Fix: if the content moved, 301 redirect instead. - Expecting Google to obey a bad canonical. As of 2026, Google treats it as a hint. Fix the underlying duplication so the hint makes sense. > In Search Console, “Alternate page with proper canonical tag” is normal when intentional. Investigate only when the canonical target is wrong for that content. ## Questions ### What is the meaning of canonical URL? It is the single URL you nominate as the original for a piece of content. You set it so search engines index and rank that version rather than its duplicates. ### How do I get or find the canonical URL of a page? Open the page source and look for a link tag with rel="canonical". Or use URL Inspection in Search Console to see both the declared and the selected canonical. ### Can you give me an example of a canonical URL? If a user lands on https://yourproduct.com/guides/getting-started?utm_source=newsletter, the canonical should be https://yourproduct.com/guides/getting-started/. The content is the same, so the clean URL is preferred. ### How can I check if a URL is canonical in Google’s index? Use URL Inspection in Search Console. It shows the Google-selected canonical. If it differs from your tag, fix duplication or signals that disagree, then request indexing. ### Should paginated or filtered pages use canonicals to page 1? Usually no. Paginated series should self-canonical so each page can be crawled. Filters that create thin or endless combinations are better handled with noindex or crawl controls. ### Is a canonical tag the same as a redirect? No. A canonical is a hint for indexing, not a user redirect. Use a 301 when a URL should not be served anymore or the content moved. ## Read next - [Canonical tags: what they do and the mistakes that cost rankings](https://porteur.ai/guides/canonical-tag): What a canonical tag does, when to use one, the mistakes that cost rankings, and how to check and fix canonicals on a small site. - [Alternate page with proper canonical tag: what Search Console means](https://porteur.ai/guides/alternate-page-with-proper-canonical-tag): What this Search Console status means, when to ignore it, when it hides the wrong page, and the exact checks and fixes to set the right canonical. - [Indexation](https://porteur.ai/glossary/indexation): Indexation means a page is stored in Google’s index and can appear in search. Here is how to check status, read Page indexing, and fix what blocks it. - [Noindex](https://porteur.ai/glossary/noindex): Noindex tells search engines not to index a page. Use it for pages that should never rank, and avoid adding it to pages that earn. - [Technical SEO checklist for a small site](https://porteur.ai/guides/technical-seo-checklist): Run these 20 technical SEO checks, in order. Each shows how to check it free and what fixed looks like for a site under 1,000 pages. - [Internal linking for a small site: which pages link to which](https://porteur.ai/guides/internal-linking-for-seo): Decide which pages rank. Build hubs, write clear anchors, fix orphans, and crawl your site to map links you control. - [Nofollow link](https://porteur.ai/glossary/nofollow-link): What a nofollow link is, what changed in 2019, how to check rel values, when to use nofollow, sponsored or ugc, and the traps to avoid. - [Canonical tags in practice: the six situations you will meet](https://porteur.ai/guides/canonical-tags-in-practice): Self-referencing canonicals, parameters, pagination, syndication and cross-domain, with the code for each and what to do when Google picks another URL. Check your site for duplicate URLs and weak canonicals with a free scan that reads your pages and rival results from your URL in about thirty seconds with three findings shown. Free check: https://porteur.ai/