How Google defines the canonical URL: 40 signals that are taken into account

In a recent episode of Google's Search Off the Record, Alan Scott from the Dups team explained how Google decides which URL to consider the main thing when there are duplicate pages. He revealed that Google looks at about 40 different signals to select the main URL from a group of similar pages.

“I am not sure what the exact number of signals is now, as it grows and decreases, but I suspect it is about 40.”

🚀 Content duplication is a common problem for search engines as many websites have several pages with the same or similar content. Google uses a process called canonization to solve this problem. This process allows Google to select one URL as the main one for indexing and displaying in search results.

• 📌 Some of the known signals that are involved in the determination of the canonical URL include: Tags RL = "CANONICAL", 301 redirection, HTTPS against HTTP, site maps, internal links, URL length.

With such a large number of signals, Alan has acknowledged that the determination of the canonical URL could be a call when the signals conflict. He said: "If your signals conflict with each other, then the system will give preference to weaker signals." This means that although strong signals, such as RL = "Canonical" and 301 redirection, are important, other factors may be affected when these signals are unclear or contradictory.