PageRank is a link analysis algorithm developed by Larry Page and Sergey Brin at Stanford University in the second half of the 1990s. Created as a tool to order the results of an academic search engine, it later became the founding criterion of Google’s ranking. Its basic principle is simple but powerful: a hyperlink from a page A to a page B is interpreted as a vote of trust that A expresses toward B.
The novelty compared to previous systems is that not all votes carry the same weight. A link from an authoritative page is worth more than one from a marginal page, and the value transmitted is split among all the outgoing links from the donating page. PageRank dominated search engine optimization strategies for over a decade, before being flanked and progressively replaced by more complex ranking systems.
The value that measures a page’s importance
PageRank is a numerical value between 0 and 1 that expresses, in summary form, the relative importance of a web page within the link graph. Formally it is a probability measure: it represents the chance that a surfer who clicks links at random, never going back, ends up on a given page after a very high number of steps.
This probabilistic interpretation is known as the random surfer model. Imagining a user who jumps from one page to another following the available links, the pages where more paths converge are the most important ones. The value calculated this way does not depend on the page’s content, but exclusively on the structure of the links around it.
When the algorithm was born and where the name comes from
The algorithm was described in a scientific paper published in 1998, the same year Google was founded. The name comes from Larry Page’s surname, but it has often also been read as a pun on the phrase “page ranking”. The original patent was filed by Stanford University and licensed to the company.
The iterations of the calculation and the original formula
PageRank is calculated iteratively. It starts with a uniform value assigned to all pages, then the score of each page is repeatedly updated based on the links it receives, until the values stabilize. The original formula includes a damping factor, generally indicated with the value 0.85, which simulates the probability that the surfer continues to follow links instead of starting over from a random page.
The value transmitted by a page is divided by the number of its outgoing links. Consequently, a page that links to many destinations transfers a smaller share of its weight to each one. This mechanism encourages careful link selection and penalizes the indiscriminate proliferation of links.
Why the damping factor is needed
The damping factor prevents the score from concentrating on a small number of nodes and ensures the convergence of the calculation. Without it, some link configurations could create closed cycles in which the value never distributes outward.
From the toolbar to today’s ranking systems
For many years Google’s toolbar showed a simplified version of PageRank, expressed on a scale from 0 to 10. This public indicator was progressively abandoned, while the internal calculation continued to evolve. Over time PageRank has been integrated into broader ranking systems that evaluate hundreds of different signals.
Today the weight attributed to hyperlinks remains relevant, but it is balanced by factors such as content relevance, user experience and the overall quality of the site. Techniques for artificially manipulating links have been countered with targeted updates, which have reduced the effectiveness of purely quantitative strategies.
Link authority and similar indicators compared
PageRank measures the authority derived from links, not editorial quality or popularity with users. It is therefore useful to distinguish it from other indicators with which it is often confused.
| Metric | What it measures | Data source | Typical scale |
|---|---|---|---|
| PageRank | Link authority | Link graph | From 0 to 1 |
| Domain authority | Overall strength of a site | Links and other signals | From 0 to 100 |
| Trust flow | Reliability of linked sources | Link quality | From 0 to 100 |
| Organic traffic | Visitors from search | Analytics | Number of sessions |
| Average position | Ranking in the SERPs | Search data | From 1 to 100 |
How to use PageRank principles in link building
Despite its reduced role, PageRank principles remain useful for guiding link building strategies and a site’s internal architecture. Understanding how value flows between pages helps distribute links rationally and enhance the most important content.
- Acquire links from authoritative sources relevant to your industry.
- Avoid large-scale link exchanges with low-quality sites.
- Limit the number of unnecessary outgoing links on key pages.
- Build an internal structure that channels value toward commercial pages.
- Use descriptive anchor text consistent with the destination content.
- Monitor inbound links to identify harmful or toxic ones.
- Enhance pillar content with targeted internal links.
- Focus on editorial quality to attract spontaneous links.
Frequently asked questions
Does PageRank still exist?
Yes, the basic concept is still integrated into Google’s ranking systems, even though it is no longer shown publicly as in the past. Today’s calculation is much more complex than the original formula.
How can you increase a page’s PageRank?
The most effective way is to obtain links from authoritative and relevant sites, as well as curating internal links. There are no reliable shortcuts: manipulative techniques are detected and penalized.
Does PageRank depend on the page’s content?
No, the original calculation is based exclusively on the link structure. Content relevance is evaluated by other components of the ranking algorithm.
What is the difference between PageRank and domain authority?
PageRank refers to individual pages, while domain authority considers the overall strength of an entire site. They are related but distinct metrics.
Does an outgoing link make you lose PageRank?
Every outgoing link transfers a share of the page’s value. However, links to authoritative sources are considered positive and should not be avoided indiscriminately.
Is PageRank an official ranking factor?
Google has confirmed on several occasions that links remain one of the signals used. PageRank in its original form, however, has merged into more articulated systems.
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Link Analysis Ranking TrustRank Inbound link Outbound link SEO and link building