Domain Authority is a score (on a 100-point scale) developed by Moz that predicts how well a website will rank on search engines. Use Domain Authority when comparing one site to another or tracking the “strength” of your website over time. We calculate this metric by combining all of our other link metrics—linking root domains, number of total links, MozRank, MozTrust, etc.—into a single score.
To determine Domain Authority, we employ machine learning against Google’s algorithm to best model how search engine results are generated. Over 40 signals are included in this calculation. This means your website’s Domain Authority score will often fluctuate. For this reason, it’s best to use Domain Authority as a competitive metric against other sites as opposed to a historic measure of your internal SEO efforts.
How is Domain Authority Scored?
We score Domain Authority on a 100-point, logarithmic scale. Thus, it’s easier to grow your score from 20 to 30 than it would be to grow from 70 to 80.
Domain Authority vs. Page Authority
Whereas Domain Authority measures the predictive ranking strength of entire domains or subdomains, Page Authority measures the strength of individual page. The same is true for metrics such as MozRank and MozTrust.
Where can you Find Domain Authority?
Domain Authority metrics are incorporated into dozens of SEO and online marketing platforms across the web.
You can measure Domain Authority using Open Site Explorer or the MozBar, Moz’s free SEO toolbar. Moz incorporates Authority metrics into all Moz Analytics campaigns, as well as the Mozscape API.
Technical Definition of Domain Authority
Domain Authority is Moz’s calculated metric for how well a given domain is likely to rank in Google’s search results. It is based off data from the Mozscape web index and includes link counts, MozRank and MozTrust scores, and dozens of other factors. It uses a machine learning model to predictively find an algorithm that best correlates with rankings across thousands of search results that we predict against.
It’s best to use Page Authority (PA) and Domain Authority (DA) as comparative metrics when doing research in the search results and determining which sites/pages may have more powerful/important link profiles than others. While specific metrics like MozRank can answer questions of raw link popularity—and link counts can show the raw quantities of pages/sites linking—the authority numbers are high-level metrics that attempt to answer the question, “How strong are this page’s links in terms of helping them rank for queries in Google.com?”
SEO Best Practice
How do I influence this metric?
Unlike other SEO metrics, Domain Authority is difficult to influence directly. It is made up of an aggregate of metrics (MozRank, MozTrust, link profile, and more) that each have an impact on this score. This was done intentionally; this metric is meant to approximate how competitive a given site is in Google.com. Since Google takes a lot of factors into account, a metric that tries to calculate it must incorporate a lot of factors, as well.
The best way to influence this metric is to improve your overall SEO. In particular, you should focus on your link profile—which influences MozRank and MozTrust—by getting more links from other well-linked-to pages.