What Is Link Equity? How Link Value Flows Through a Site
Link equity is the SEO term for the value a link passes from one page to the page it points to. The idea comes from PageRank, the link analysis method Larry Page and Sergey Brin described in 1998, which treated a link as a kind of vote whose weight depended on the importance of the page casting it. Value enters a site mainly through links from other sites and moves between pages through the site’s own links. Google’s systems today use far more than that early formula, so link equity is a model for reasoning about links, not a number anyone can read.
Where the Idea Comes From
In “The Anatomy of a Large-Scale Hypertextual Web Search Engine”, Brin and Page defined a page’s PageRank from the pages linking to it. Each linking page contributes its own PageRank divided by “the number of links going out of page A,” and the sum is multiplied by a damping factor, which the authors usually set to 0.85. They explained the model with a “random surfer” who follows links and occasionally jumps to a random page; a page’s PageRank is the probability that the surfer lands on it.
Google still describes link analysis as part of ranking. Its guide to ranking systems refers to “various systems that understand how pages link to each other,” among them PageRank, “one of our core ranking systems used when Google first launched.” It adds: “How PageRank works has evolved a lot since then, and it continues to be part of our core ranking systems.”
A Worked Example of the 1998 Formula
Under the 1998 formula, a page passes its value in equal shares to every page it links to, multiplied by the damping factor. Take a linking page with a PageRank of 1 (an illustrative value):
| Outbound links on the linking page | Share passed to each target (0.85 × 1 ÷ links) |
|---|---|
| 4 | 0.2125 |
| 20 | 0.0425 |
| 100 | 0.0085 |
The same link is worth 25 times more in the first row than in the last, which is where the idea of “dilution” comes from. Two cautions apply. The numbers describe the published 1998 model, not any score Google shows or uses today. And Google later described a model in which links are not equal.
Not All Links on a Page Are Equal
A Google patent granted on February 14, 2012, US 8,117,209, describes “a reasonable surfer model that indicates that when a surfer accesses a document with a set of links, the surfer will follow some of the links with higher probability than others.” Instead of an equal split, each link’s weight depends on features such as where it sits on the page and how prominent it is. Google Patents lists the patent as expired. A patent shows an approach Google protected, not proof of what its systems do now, but it explains why a link in the body of an article and a link in a footer are not assumed to be worth the same.
Link attributes also change what a link passes. In a September 10, 2019 post, Google said it would treat nofollow, sponsored, and ugc as hints about which links to consider, and added: “For crawling and indexing purposes, nofollow will become a hint as of March 1, 2020.”
External and Internal Equity
- External equity comes from other sites linking to yours. It is the harder kind to earn, because someone else decides your page deserves the link.
- Internal equity is how your own links distribute what the site has. Internal links cannot create authority from outside, but they decide which pages receive the value that strong pages hold.
Google’s link best practices set the floor: “Every page you care about should have a link from at least one other page on your site.” They also set no ideal number of links per page. A page with no internal links pointing to it receives nothing from the rest of the site, and crawlers have no internal path to it.
What Interrupts the Flow
- Broken internal links point value at nothing.
- Redirect chains add hops before the final page; link straight to the final URL.
- Duplicate URLs split links that should consolidate on one page; choose a canonical and link to it.
- Templates that repeat the same links on every page give every page the same targets; contextual links show which pages matter for a topic.
Equity and Link Schemes
Because links carry value, they are a target for manipulation. Google’s spam policies put buying or selling links for ranking first among link spam practices, and accept paid links only when they carry a nofollow or sponsored attribute. Equity that arrives through a scheme can be ignored by Google’s systems or lead to a manual action, and either outcome removes the value the scheme was meant to add.
Questions About Link Equity
Is link equity the same as PageRank?
PageRank is Google’s original algorithm; link equity is the broader SEO term for the value links pass. Google says PageRank remains one of its core ranking systems, alongside many others.
Should every page link to every other page?
No. Linking everything to everything gives every page the same internal signal, and the 1998 model splits a page’s value across all of its links. Link where the destination helps the reader of that page.