URL Canonical Checker
Enter a page address and see which URL it declares as canonical, from the rel=canonical tag in the HTML and from the HTTP Link header. The checker follows redirects to the final page, reports conflicting or misplaced tags, and requests the canonical target to make sure it does not redirect or return an error.
- Encrypted connection
- No sign-up
- Free to use
How to use URL Canonical Checker
- Enter the URL of the page.
- Wait while the page and its canonical target are fetched.
- Read the canonical URL and the checks.
- Fix any failures in the page template.
URL Canonical Checker features
Tag and header
Reads <link rel="canonical"> and the Link HTTP header.
Conflict checks
Several tags, tag versus header, tag in the body.
Target check
Requests the canonical URL to catch redirects and errors.
Protocol and robots
Flags http canonicals and noindex conflicts.
og:url comparison
Shows when social sharing uses a different URL.
Safe fetching
Only public addresses; private networks are blocked.
When to use URL Canonical Checker
- Checking a template after a redesign.
- Debugging duplicate-content warnings in Search Console.
- Verifying canonicals on filtered and paginated pages.
- Auditing a competitor’s handling of URL variants.
URL Canonical Checker FAQ
What is a canonical URL?
The preferred address of a page that is reachable under several URLs, for example with tracking parameters or in different sort orders. The canonical tag tells search engines which one to index.
Should every page have a canonical tag?
It is good practice to have a self-referencing canonical on every indexable page, which removes ambiguity about URL variants.
Why must the canonical not redirect?
Search engines treat a canonical pointing at a redirect as a weak or contradictory signal. Point it at the final URL.
Is the canonical a directive?
It is a strong hint. Search engines may ignore it if other signals, such as internal links and sitemaps, point elsewhere.
Can I check private or local sites?
No. For security the tool only fetches public internet addresses.
What is the Link header canonical?
An HTTP header that declares the canonical, used for non-HTML files such as PDFs.
One page, many addresses
The same content is often reachable under many URLs: with and without a trailing slash, with tracking parameters, in different sort orders, over http and https. Search engines try to group these duplicates and pick one address to show, and the canonical tag tells them which one you prefer.
A canonical only helps when it is consistent. Two different canonical tags cancel each other out. A tag placed in the body instead of the head is ignored. A canonical that points at a redirect, an error page or the http version of an https page sends contradictory signals. Each of these is easy to introduce in a template and hard to see in the browser, which is why the checker looks for them.
The HTTP Link header is the canonical mechanism for files without HTML, such as PDFs. When a page has both a tag and a header, they should agree. The checker compares them and also looks at og:url, which social networks use when the page is shared.
Canonical tags are one signal among several. Internal links, sitemaps and redirects should all point to the same preferred URLs. When they do, search engines follow the canonical reliably; when they do not, they may choose differently.