Short answer
A canonical tag is a line in a page's head, written as link rel="canonical", that tells search engines which address is the main version of that content. Use it when the same or very similar content is reachable at several addresses, such as with tracking codes, sort options or print versions. Google treats it as a strong hint, not a command, so your links and sitemap must agree with it.
Why one page can have many addresses
To you it is one page: your blue cotton kurta. To a search engine, these may all be different: the product address, the same address with ?colour=blue, with a Facebook tracking code, under two category paths, with and without www, and over http and https. Without guidance, Google picks one itself, and it may not pick the one you want.
The canonical tag says: "of all these, this is the address to show in search".
How to write it correctly
- Place it inside the head section of the page, once.
- Use the full address, including https and your domain.
- Point to a page that loads with a 200 code, not a redirect or an error.
- Give the main version a canonical pointing to itself. This self-referencing tag protects it from tracking-code copies.
- Keep it consistent with your sitemap and internal links, which should all use the same address.
When to use a canonical, and when not to
Use it for true duplicates and near-duplicates: filtered or sorted lists, printer-friendly pages, the same product in two categories, or an article you republished on another site with permission.
Do not use it to merge pages that are genuinely different, such as two separate services, or page 2 and page 1 of a blog list. Do not use it as a replacement for a redirect when a page has really moved; a 301 redirect is clearer.
Mix-ups that confuse Google
- Every page on the site pointing its canonical to the home page, usually a theme or plugin setting gone wrong.
- A canonical pointing to a page that is noindex, blocked or redirecting.
- The sitemap listing one address while the canonical names another.
- Two canonical tags on one page, often from a theme and an SEO plugin both adding one.
- Language versions pointing their canonical at the English page, which can hide the Hindi or Punjabi page.
Checking which version Google chose
In Google Search Console, the URL Inspection tool shows the canonical you declared and the one Google selected. If they differ, look for mixed signals: internal links to the other version, the other version in the sitemap, or content that is not actually the same.
What AI Marketing Master checks
The website audit looks at canonical tags on every page it crawls and flags pages where the tag is missing or points somewhere unexpected, in plain words with a suggested fix. Canonical tags are set in your theme, CMS or SEO plugin, so the change is made there; the next audit confirms it.
What it does not do
- AI Marketing Master reports canonical problems. It does not change canonical tags on your site; WordPress auto-fix covers only titles, meta descriptions and image alt text.
- The audit cannot see which canonical Google finally chose. Use URL Inspection in Search Console for that.
Questions people ask
Does every page need a canonical tag?
It is good practice. A self-referencing canonical on each page protects against copies created by tracking codes and filters.
Will Google always follow my canonical?
Usually, but not always. It is a hint. If your links, sitemap or redirects point elsewhere, Google may choose a different address.
Is a canonical the same as a redirect?
No. A redirect sends people to another address. A canonical leaves the page reachable but tells search engines which version to show.
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