Page Authority
What is Page Authority?
Page Authority (PA) is a score developed by Moz that predicts how well a specific page will rank on search engine result pages (SERP). Page Authority scores range from one to 100, with higher scores corresponding to a greater ability to rank.
Tools: Check your PA with Link Explorer
Page Authority is based on data from our web index and takes into account dozens of factors. Like Domain Authority, it uses a machine learning model to identify the algorithm that best correlates with rankings across the thousands of SERPs that we predict against, then produces Page Authority scores using that specific calculation.
How is Page Authority scored?
We score Page Authority on a 100-point logarithmic scale. Thus, it's significantly easier to grow your score from 20 to 30 than it is to grow from 70 to 80. We constantly update the algorithm used to calculate Page Authority, so you may see your score fluctuate from time to time.
What is a "good" Page Authority?
Because of how Page Authority is calculated (see "Technical definition of Page Authority" below), it's best used as a comparative metric (rather than an absolute, concrete score) when doing research in the search results and determining which pages may have more powerful or important link profiles than others. Because it's a comparative tool, there isn't necessarily a "good" or "bad" Page Authority score.
Page Authority vs. Domain Authority
Whereas Page Authority measures the predictive ranking strength of a single page, Domain Authority measures the strength of entire domains or subdomains. The metrics are, however, calculated using the same methodology — so in many ways, they're more alike than they are different.
Where can you find Page Authority?
Page Authority metrics are incorporated into dozens of SEO and online marketing platforms across the web.
In the Moz ecosystem, you can check Domain Authority using Link Explorer, MozBar, Moz's free SEO toolbar, or in the SERP Analysis section of Keyword Explorer. Authority metrics are also incorporated into all Moz Pro campaigns, as well as our API.
Technical definition of Page Authority
Page Authority is calculated in the same way as Domain Authority, but at the individual page level. Page Authority is based off data from the Mozscape web index and includes link counts and dozens of other factors (more than 40 in total). Importantly, it does not take into consideration specific on-page elements like keyword use or content optimization.
Like Domain Authority, Page Authority is calculated using a machine learning algorithm and thus will fluctuate as the data being fed into the algorithm changes. For this reason, it's best to use Page Authority as a relative metric to compare against other pages as opposed to an absolute value "scoring" the the rankability of any one page.
How do I influence Page Authority?
Like Domain Authority, Page Authority is a holistic score and difficult to influence directly. It is made up of an aggregate of metrics that each have an impact on the score. This multi-factorial dependence is intentional: Since Google takes a lot of factors into account when ranking a page, a metric that tries to calculate it must incorporate a lot of factors, as well.
The best way to influence a page's Authority is to improve its link profile. This can be accomplished by getting external links from other high-authority pages, which in turn act as "votes of confidence" for the authority of your page.
Why did my Page Authority change?
Page Authority depends on many factors, and thus can fluctuate for a wide number of reasons. More information about why Page Authority changes and a model for interpreting those fluctuations can be found in the “Why did my Authority change?” section here.
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Link Explorer is a link popularity and backlink analysis tool that lets you research and compare any site on the web.