PageRank and Link Equity

PageRank is the algorithm Google was built on. Published by Larry Page and Sergey Brin in 1998, it treats links as votes: a page linked to by many authoritative pages is likely more valuable than one that is not. Decades of refinement have layered far more complexity on top of that original model, but the underlying principle, that links transfer authority, remains central to how Google ranks pages.

Understanding how link equity flows explains both why backlinks matter and how internal linking decisions affect which pages can rank.

What is PageRank?

PageRank assigns a numerical score to each page based on the quantity and quality of links pointing to it. A link from a high-PageRank page passes more equity than a link from a low-PageRank page. The system is iterative: a page’s score depends on the scores of the pages that link to it, which in turn depend on the scores of the pages that link to those, and so on across the entire web graph.

Google retired the public PageRank toolbar score in 2016. The metric has not been visible externally since. Links remain one of Google’s most heavily weighted ranking signals, and PageRank logic continues to operate internally within the ranking algorithm.

Third-party authority metrics (Domain Rating from Ahrefs, Domain Authority from Moz, URL Rating from Ahrefs) are proxies that attempt to model similar signals from publicly visible link data. They approximate PageRank principles but are not Google metrics and do not directly determine rankings.

How does link equity flow?

When a page receives external links, it accumulates equity. When that page links out to other pages, it distributes a portion of its equity through those outbound links.

The central mechanic: a page’s outgoing link equity is divided among its outbound links. A page with two outbound links passes roughly half its available equity through each. A page with twenty outbound links passes roughly one-twentieth through each. The total equity distributed does not exceed what the page holds.

This is why links from pages with few outbound links are more valuable than links from pages with many. A link from a page that links to only three other sites passes substantially more equity than a link from a page linking to two hundred.

What determines how much equity a link passes?

Several factors determine the value of an individual link:

The linking page’s authority. A link from a high-authority page passes more equity. The linking domain’s overall authority contributes to the individual page’s authority.

The number of outbound links. Equity is divided among outbound links. Fewer outbound links on the linking page means a larger share passes through each one.

Placement. Editorial links within body content carry more weight than links in footers, sidebars, or boilerplate template sections. A link an editor chose to include signals genuine endorsement more clearly than one that appears identically across thousands of pages.

Topical relevance. The relationship between the linking page’s topic and the linked page’s topic matters. A link from a closely related page passes more topical relevance signal than a link from an unrelated domain.

Link attributes. Standard links pass equity. Links marked rel="nofollow" are treated by Google as hints rather than directives and generally do not pass the same equity. Links marked rel="sponsored" or rel="ugc" signal the nature of the link and are handled similarly. High-traffic nofollow links from major publications still drive referral visits and build brand signals, but do not pass link equity the way standard editorial links do.

How do internal links distribute link equity?

External backlinks bring equity into your domain. Internal links determine where that equity goes within it.

A site’s homepage typically accumulates the most external links, making it the highest-equity page on most sites. Internal links from the homepage pass equity to the pages it links to. Those pages pass equity to pages they link to, and so on through the site’s internal link graph.

Pages that receive many internal links from high-equity pages accumulate more equity than pages buried several clicks from the homepage with only one link pointing to them. This is why the most important pages, including key product pages, target category pages, and content you want to rank, should be accessible from the homepage and linked to from many internal pages.

Flat architecture distributes equity more broadly. A site where all important pages are reachable within two clicks keeps equity from concentrating at the top levels. Important content buried five levels deep with one link pointing to it receives minimal equity regardless of how many external links the site has.

Anchor text in internal links carries relevance signals. The text of an internal link signals what the linked page is about. Descriptive anchor text helps Google understand the topic of the linked page more clearly than generic anchor text (“click here”, “read more”). This is distinct from external anchor text optimisation, where over-optimisation looks manipulative. Internal links with accurate, descriptive anchor text are a standard practice.

What is the practical implication for backlink strategy?

Link equity from external backlinks increases the total equity available to your domain. A single high-quality link from a relevant, authoritative publication can move rankings more than dozens of low-quality directory submissions because of the equity it adds to the system.

However, where a link points matters as much as who links. A link to your homepage builds domain authority broadly. A link directly to a target page builds that page’s ability to rank for its specific queries. When planning link building campaigns, identify which pages most need equity, typically the pages targeting the most competitive queries, and direct outreach at earning links to those pages specifically rather than defaulting to homepage links.

What has changed since the original PageRank model?

The original model treated all links as equal except for their equity weight. Google’s current link evaluation is substantially more nuanced:

Quality assessment. Google identifies and discounts links from low-quality, untrustworthy, or specifically-created-to-pass-links sources. Link building at scale through paid placements, networks, or exchanges exploits the link equity model but is identified and addressed through algorithmic and manual enforcement. See backlink audit and disavow for the framework.

Topical relevance. Link equity is not purely determined by authority. The topical relevance of the linking domain and page contributes to the relevance signal a link provides to the linked page.

Link pattern evaluation. Sudden large link gains from low-quality sources, or profiles that look unnatural in their acquisition pattern, trigger algorithmic scrutiny. Natural link profiles accumulate gradually from diverse, relevant sources over time.

The foundational logic holds: links transfer authority, internal links redistribute it, and pages that receive the most equity from the strongest sources rank more easily for competitive queries. What has changed is the sophistication with which Google evaluates whether that authority transfer reflects genuine editorial endorsement.