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Definition

What is Canonical URL?

A canonical URL is the single, preferred web address for a page — declared with a <link rel="canonical"> tag so search engines consolidate ranking signals on one version.

Also called: rel canonical · canonical tag

The same page can be reachable at http and https, with and without www, with tracking parameters, or via a category and a tag. Without a canonical tag, Google may split link equity between those variants or index the wrong one.

A canonical tag is a single line in the <head>: <link rel="canonical" href="https://example.com/page"/>. It tells crawlers 'this is the master version — treat all the others as duplicates of me'.

Every indexable page on a modern site should self-canonicalise. Get it wrong and organic traffic quietly leaks to a URL variant you didn't mean to promote.

Try a tool that uses Canonical URL

Canonical Tag Generator

Generate a clean canonical link tag for any URL.

Meta Tag Generator

Generate SEO-friendly title, description, Open Graph and Twitter meta tags.

SEO Audit Tool

Audit on-page SEO factors from any HTML source in seconds.

Related definitions

Meta Description

A meta description is a short HTML tag that summarises a page — Google often uses it as the grey snippet under the blue link on the search results page.

Open Graph

Open Graph is a set of <meta property="og:…"> tags, invented by Facebook, that control how your page looks when someone shares the link on social media or chat apps.

Schema Markup (Structured Data)

Schema markup is structured data — usually JSON-LD in a <script> tag — that describes a page's contents in schema.org vocabulary so search engines can render rich results.

robots.txt

robots.txt is a plain-text file at the root of a website that tells web crawlers which paths they may or may not fetch.