What Is a Canonical URL?
A canonical URL is the one main web address you choose for a page. When you have several pages that are the same or very close, the canonical URL tells search engines which page is the real one to use.
Definition
A canonical URL is the preferred version of a web page that you want search engines like Google to index and rank. You usually set it with a special line of code called a rel="canonical" tag in the head section of your HTML.
This tag points to the main page address and says, in simple words, “If you find similar pages, treat this URL as the main one.”
Why Canonical URL Matters
- Stops duplicate content problems If many pages say the same thing, search engines can get confused. A canonical URL clears that up.
- Combines ranking power Links and signals from similar pages can be joined together and given to the main page.
- Makes search results cleaner Users see the best version of your content, not many copies of the same page.
- Gives you more control You help search engines understand which page you care about the most.
How Canonical URL Works
When search engines crawl your site, they may find many URLs with almost the same content. For example, a product page with different sorting or tracking codes in the URL.
On each of those similar pages, you can add a canonical tag that points to the one main page address. For example:
<link rel="canonical" href="https://www.example.com/shoes/red-shoes">
Search engines read this tag and usually treat the URL in the href as the main version. They focus crawling, indexing, and ranking on that canonical URL and may show it in search results.
Canonical URL vs Related Terms
Canonical URL vs 301 redirect
- A 301 redirect moves users and search engines from one URL to another. The old URL does not stay active.
- A canonical URL keeps all URLs live but tells search engines which one is preferred. Users can still visit the other URLs.
Canonical URL vs sitemap URL
- A sitemap lists important URLs on your site.
- A canonical URL is a signal that one page version is the main one. Often, only canonical URLs should appear in your sitemap.
Example of Canonical URL
Imagine you sell a red shoe and you have these URLs:
https://www.example.com/shoes/red-shoeshttps://www.example.com/shoes/red-shoes?color=redhttps://www.example.com/shoes/red-shoes?ref=newsletter
All three pages show the same product. You choose the clean URL as the canonical URL:
https://www.example.com/shoes/red-shoes
On the two other URLs, you add this tag in the head:
<link rel="canonical" href="https://www.example.com/shoes/red-shoes">
Now search engines know to treat the clean URL as the main page.
FAQs
Q: Do I need a canonical URL on every page
A: It is a good idea. Even if a page has no copy now, setting a self canonical tag to its own URL can prevent problems if similar pages appear later.
Q: Will Google always follow my canonical URL
A: Not always. Google tries to respect your tag but may pick a different URL if it thinks another page is a better main version. Clean, consistent URLs help Google agree with your choice.
Q: Can I set a canonical URL across different domains
A: Yes, you can point the canonical to a page on another domain, for example when you syndicate content. But both sites should trust each other and the content should be truly the same.
Q: What happens if I use the wrong canonical URL
A: You might send ranking power to the wrong page and hide the page you actually want to rank. Always double check the URL in your canonical tag.
