Central to understanding how to flow authority through your site is an understanding of PageRank. Named for Google founder Larry Page, PageRank was the central premise that Google was designed around. In the years since Google launched it has grown in sophistication and now PageRank is just one small piece of the ranking puzzle. In terms of on-site authority work the PageRank model remains one of the most important pieces — it appears that other link-related benefits flow through a site similarly to PageRank.
PageRank is a measure of the raw link juice that flows through links into any given page on the internet.
In Google’s model, every link a page receives is like a vote of confidence saying that the page has good and useful content. The more links a page has, the more confident Google is in ranking that page.
PageRank is a measure on a scale of 1-10 of how much raw link authority a page has. But PageRank isn’t just a measure of the number of incoming links: a link from a high authority page is worth much more than a link from a low authority page. So PageRank calculates link authority based on all the incoming links to a page, and the incoming links to the pages that link to that page, and of course the incoming links to the page that links to the page that links to that page all the way back forever — it’s turtles all the way down.
The very clever thing about PageRank was the math that was able to calculate the PageRank value of every site based on an infinite chain of linking sites. But for our purposes, the important thing is that more authoritative sites are worth more.
How Do I Find Out My PageRank Is?
Put simply, you can’t.
Google used to share a version of PageRank publicly, called Toolbar PageRank. It was never a very precise measure, but it let SEOs at least track major growth in authority. Google no longer provides this, however.
Happily, you don’t need to know what your PageRank is to optimize your site.
How PageRank Flows
The PageRank of a page flows through the links on that page — or at least most of it does. Due to the way the PageRank model works, only 85% of a page’s PageRank flows out through links.
That PageRank is then divided by the number of links on a page, and a proportional amount flows through each link.
Thus if we had a page with a PageRank 10, and we had a total of 10 links on the page: 8.5 total PageRank would flow through the links (because only 85% of it flows out) and each page we’re linking to would get .85 PageRank from us. If instead we had 100 links on the page then each link would get .085 PageRank from us.
It’s worth clarifying that none of this reduces the PageRank of our page at all. The number of links you have on a page does not affect that page’s PageRank at all, and certainly doesn’t lower it. PageRank is often pictured as a bucket with water flowing out of each hole: this is the one area where that comparison breaks down. While PageRank flows through every link, it never actually takes away from the existing page. PageRank is calculated solely on incoming links from other pages.
It’s also worth noting that nofollow links (which we’ll discuss later in this section) don’t flow PageRank, but they still count as part of the link total that that PageRank gets divided by.
Thus if we had our PageRank 10 site with 5 nofollow links and 5 normal links: 8.5 total PageRank would be available to flow through the links (because only 85% of it flows out); the nofollow links would get no PageRank and the normal links would get .85 PageRank each — because we’re still dividing the available 8.5 by 10 links, even though half the links aren’t getting anything.
Almost as soon as the nofollow tag was created by Google in 2005, SEOs started “PageRank sculpting” by putting nofollow on nearly all of their internal links to control exactly how the PageRank flowed through their sites (and suffice to say they nofollowed every external link). Google very quickly (also in 2005) changed the PageRank calculation so that nofollow links still counted when calculating the PageRank that flowed through links (as I describe above).
The only way you can increase your PageRank is by getting more links pointing to the page — and preferably links from higher PageRank sites. The only way you can control how much PageRank flow out through your links is by changing the number of total links on the page.
PageRank vs Link Juice
Technically PageRank is one part of the authority that passes through links that Google measures. SEOs often use the term Link Juice to more broadly describe all benefits that pass through link; however, in the SEO world PageRank and Link Juice are used interchangeably.
When Google talks, however, and they talk about PageRank, they usually mean just PageRank, and not necessarily all authority factors that pass through links.