Google PageRank: What It Is & How the Algorithm Works
Search engine optimization (SEO) is fraught with niche terminology and complex concepts. One such concept that’s been subject to much hullabaloo for no less than 20 years is Google’s PageRank algorithm. Even if you’re not quite sure what PageRank means, you’re likely familiar with how many digital marketers are quite concerned with it.
There’s a lot to learn if you want to fully understand what PageRank is, how it works, and how to improve your website’s PageRank. Thankfully, you’ve come to the right place – keep reading and we’ll teach you all the basics.
What is PageRank?
PageRank is one of Google’s many algorithms, designed to assess a website’s quality and determine its position on the Search Engine Results Page (SERP) for a given query. The higher your PageRank score is, the more likely it is to rank for a given target keyword. While PageRank is not the only ranking factor that Google considers, it is regarded as one of the most important components of Google’s site ranking process.
The link analysis algorithm is complex, but its general behavior is fairly simple. Let’s provide a basic overview of how the algorithm works using two hypothetical websites we’ll call Website A and Website B. Website A is a highly authoritative business news website, while Website B is an emerging consumer packaged goods company.
As Google’s crawlers scan web content from across the internet, they come across a recent news article by Website A. While they’re analyzing the content on Website A’s new article, they also scan for links that point to other websites. In this case, there’s a link on Website A that points to Website B.
Google’s crawling bots note that Website A linked to Website B. When it makes this connection, it assumes that Website A – a highly credible website – would only link to other credible websites. Through this association, Google begins to perceive Website B as somewhat more trustworthy than it did earlier that day.
As websites collect more links from credible websites, their PageRank score will continue to rise. With that said, quality is key. One link from a quality website is better than a thousand links from a low quality website.
PageRank According to Google
PageRank isn’t a term invented by the SEO industry. In fact, it is directly mentioned in Google’s philosophy page. Here’s how Google describes PageRank:
“We assess the importance of every web page using more than 200 signals and a variety of techniques, including our patented PageRank™ algorithm, which analyzes which sites have been “voted” to be the best sources of information by other pages across the web. As the web gets bigger, this approach actually improves, as each new site is another point of information and another vote to be counted.”
Google describes this as a form of democracy on the web. However, while PageRank is almost like a voting system, keep in mind that Google doesn’t value votes equally. A vote from The New York Times will matter more than a vote from your local radio station’s blog.
How Does Google Calculate PageRank Score?
The exact details of how Google calculates PageRank aren’t known to anyone outside of Google’s HQ. However, one thing is certain: It’s a complicated algorithm. For example, here’s an excerpt from Google’s first PageRank patent:
“[The below image] shows a typical relationship between three hypertext documents A, B, and C. As shown in this particular figure, the first links in documents B and C are pointers to document A. In this case we say that B and C are backlinks of A, and that A is a forward link of B and of C. Documents B and C also have other forward links to documents that are not shown.”
While the formula may have changed slightly over the years, Google’s Search Liaisons have confirmed the search engine uses an improved version of this original PageRank algorithm.
After running this algorithm, a site would be assigned a PageRank score between 0 and about 65,000. While Google doesn’t share a site’s precise score, they did provide a simplified score for Google Toolbar users throughout the early 2000s. A PageRank of 1 meant you had few links, and the links you did have were low value. A PageRank of 10 meant you had an incredible number of high-quality links pointing to your website. Google would openly present this number to anyone who downloaded their free toolbar throughout the early 2000s, helping them understand how Google valued their website.
If you’re active in the SEO community today, I know what you’re thinking – “That must have been nice.”
A lot has changed in the past 20 years or so. Even though today’s websites still get a PageRank score, Google doesn’t provide a public-facing score anymore. While that might seem frustrating, there’s a reason why Google had to hide PageRank behind a black box. To see why that change happened, let’s run through a quick history of PageRank.
A History of Google PageRank
Google may be secretive about how PageRank works – but the history of the algorithm can give us some valuable insight into how it works. Let’s look at some of the most major occurrences in PageRank’s history.
1996: The Early Beginnings
The story of PageRank starts in 1996, when the earliest algorithm that resembled PageRank was crafted. Interestingly, this algorithm wasn’t created by Google; it was created by a man named Robin Li, who was working on a site-scoring algorithm called RankDex. RankDex was used to score websites based on how many other sites linked to it – the more links your site got, the better it performed.
At around the same time, two Stanford University PhD students, Larry Page and Sergey Brin, were working on a search algorithm to help people find information on the world wide web. They used all the information available to them – including Robin Li’s research for RankDex.
Two years later, Page and Brin had made significant progress on their search algorithm and patented it under the name PageRank. And in just a few more months, that same duo of Stanford researchers founded Google.
You may be wondering what happened to Robin Li and his RankDex creation throughout all of this. Don’t worry – his hard work wasn’t unrecognized. He later went on to found Baidu, the most popular search engine in China.
2000: Introducing the Google Toolbar
The internet was still relatively new in the early 2000s – in fact, only about half of all households even had a computer at that point. But the popularity of the internet (and searching on the internet) was growing fast. In 1998, the Google search engine was processing 10,000 searches per day. In 1999, Google was processing over 3 million searches per day. In 2000, Google was processing 42 million searches per day.
To help these searchers and cement their position as a leader in a new, booming industry, Google released the Google Toolbar. It provided a lot of capabilities that were super useful for its time, like the ability to access bookmarks or search Google without navigating to Google.com.
However, it also provided users with the ability to check the authority of a website they were visiting with a PageRank score between 1 and 10.
In the 2000s, businesses and hobbyists started to see the value of their page appearing in a prominent position on Google Search. For early SEOs, there was a clear roadmap: PageRank influenced how your site ranked on Google. PageRank was decided by how many links you had. And you could get a simple metric to help you accurately track your PageRank score through the toolbar.
Of course, people immediately started gaming the system. During this time, businesses started negotiating with each other to trade links. Businesses bought hundreds or thousands of low quality links from “link farms” for a small fee. Black hat SEO was running amok. Google quickly realized that they needed to shake things up, or risk a poor user experience.
2006: Google Makes Serious Changes to PageRank
The wild west of PageRank manipulation could only go on for so long. In 2006, Google filed an updated (and more secretive) patent for an upgraded version of their PageRank algorithm. On top of this, an ex-Google employee reported that the original PageRank algorithm was retired before the end of 2006. This made 2006 a major year for both Google and PageRank.
By examining the new patent, some key differences were made clear. Certain sites were regarded as “trusted” – the New York Times and Google Directory, for example. When these “trusted” sites linked to a page, that page gained some trust as well. Then, when that page linked to a different page, they would pass on some of that credibility to the other site.
This made it a lot harder to engage in link trading and link farming, although those black hat tactics never truly went away. To continue to combat unsavory SEO practices, Google continued to tweak this existing PageRank algorithm while adding other capabilities to their algorithm, like RankBrain and Core Web Vitals.
2019: The Original PageRank Patent Expires
The years between 2006 and 2019 are shrouded in mystery, with Google rightfully becoming tightlipped regarding their algorithms. However, in 2019, the original patent expired without any attempt of a renewal. While Google’s liaisons have reported the original algorithm is still in use, the change of patents suggests that the original algorithm has been heavily reworked nonetheless.
How Does Google’s PageRank Algorithm Work Today?
In 2020, Google gave firm confirmation that PageRank is still important to Google’s search algorithm. Although Google still won’t share the specifics of how PageRank works, Search Advocates like John Mueller are happy to drop a few hints to help SEOs. For example, during a Google SEO Office Hours event in 2021, Mueller confirmed that one good link is worth more than millions of poor quality links.
Keep in mind that while PageRank may be a confirmed ranking factor, Search Advocates have also confirmed it matters more for some searches than others. While it’s not clear which queries PageRank is important for, it’s easy to imagine that sites dispensing medical advice may need a higher PageRank score than a website providing business advice.
Looking back through the history of PageRank, one thing is clear: Its influence on SERPs has dwindled over time. Today, Google is incredibly sophisticated – and their espoused goal is to serve users with relevant, high quality content. While your PageRank provides a clue to your content quality, Google understands it’s far from the only factor.
Which Factors Influence PageRank?
Before we get into this list, it’s worth mentioning that many of these factors are speculative. Google is well-aware that the many SEOs want to game their algorithm, so they try not to share their secret sauce. However, due to the age and importance of PageRank, experienced SEO professionals have some theories about what works. Let’s dig in:
1. Quality of the Referring Site
It may seem obvious, but the PageRank (or the trusted seed status) of a referring site is the most important factor in determining your PageRank. The logic is that high quality sites prefer to refer traffic to other high quality sites.
On that same note, too many low quality sites can bring down your PageRank. Don’t stress if you have a few spammy links pointing to your website, or if you’ve naturally picked up some low quality links over time. Google accounts for situations like that in their algorithm. However, never agree to buy a large quantity of backlinks from a dubious source. This will either damage your PageRank or, best case, have no impact on your PageRank at all.
2. Internal Links
Internal links, which are when you link to your website’s content on your own website, do influence PageRank, but there’s a catch. Internal links don’t increase your website’s overall PageRank. However, according to John Mueller, a good internal linking structure will ensure that your PageRank score is properly distributed throughout your website.
3. Clickthrough Rate
Clickthrough rate isn’t a confirmed ranking signal – but many SEOs think it may be. This is because Google’s PageRank algorithm has used a “Reasonable Surfer Model” in the past. This model uses “different features of a link from a linking document to a linked document and user behavior data relating to navigational actions associated with the link.”
While Google has been quiet about the Reasonable Surfer Model for a while, the patent keeps getting extended – so, Google clearly wants to hang onto that technology. Based on this, it’s fair to say a user’s behavior on a page that links to you matters in some way. While it’s not crystal clear as to whether or not this is referring to a link’s clickthrough rate, many SEO experts choose to interpret it in that way.
4. Anchor text
Anchor text, which is text that is used to hyperlink to another online resource, is unconfirmed to influence your PageRank. However, the context around your anchor text is confirmed to be extremely valuable to Google. Additionally, people are more likely to click on a link surrounded by relevant and interesting content, which can result in positive user behavior.
While anchor text may not be a confirmed PageRank factor, paying attention to your anchor text is certainly an SEO best practice. If you have any control over what your link’s anchor text says, surround it with meaningful, rich text.
5. Follow/Nofollow links
This is commonly cited as a PageRank factor – and it was confirmed that NoFollow links didn’t pass PageRank back in 2017. However, there’s plenty of evidence to suggest this is no longer a significant contributor to PageRank after 2022. Now, Google treats nofollow links as a “hint,” so they may choose to pass PageRank anyway. This decision may have been to cut back on a practice called PageRank Sculpting.
Does PageRank Still Matter to Google?
PageRank does still matter in Google’s overall search algorithm. However, it’s not the only ranking signal they use – and depending on the query, it may not be the most important ranking signal either. This has been confirmed in a 2020 tweet by John Mueller, a Search Advocate at Google.
Yes, we do use PageRank internally, among many, many other signals. It’s not quite the same as the original paper, there are lots of quirks (eg, disavowed links, ignored links, etc.), and, again, we use a lot of other signals that can be much stronger.
— John Mueller is mostly not here ? (@JohnMu) February 24, 2020
Is There a Way to Check Your PageRank?
Unfortunately, Google does not provide a method to check your PageRank.
If you’d like an estimate, however, there are a few SEO tools that can help. For example, Moz uses a metric called Domain Authority and SEMRush uses a metric called Authority Score. A high Domain Authority or Authority Score should be a general indicator of a site’s authority, but it doesn’t use Google’s proprietary PageRank algorithm. While it’s a helpful metric to watch, it is by no means a direct analog to PageRank.
Conclusion
While PageRank is still in active use by Google, remember that we’ve come a long way since the year 2000. Now, Google uses countless ranking factors in addition to PageRank. While that might make life a little harder for SEO experts, a more balanced and nuanced search algorithm is overall beneficial to searchers. As time continues to pass, we can only anticipate that Google’s algorithms will grow in complexity.
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