Domain Authority What is Domain Authority? Domain Authority (DA) is a search engine ranking score developed by Moz that predicts how well a website will rank on search engine result pages (SERPs). A Domain Authority score ranges from one to 100, with higher scores corresponding to a greater ability to rank. How is Domain Authority scored? We score Domain Authority on a 100-point, logarithmic scale based on a website's popularity, MozRank, MozTrust, etc. Thus, it's significantly easier to grow your score from 20 to 30 than it is to grow from 70 to 80. Because of how Domain Authority is calculated (see "Technical definition of Domain 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 sites may have more powerful/important link profiles than others. Because it's a comparative tool, there isn't necessarily a "good" or "bad" Domain Authority score. 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 pages. Where can you find Domain Authority? Domain Authority metrics are incorporated into dozens of SEO and online marketing platforms across the web. Technical definition of Domain Authority Domain Authority is based on data from the Mozscape web index and includes link counts, MozRank and MozTrust scores, and dozens of other factors (more than 40 in total). The actual Domain Authority calculation itself uses a machine learning model to predictively find a "best fit" algorithm that most closely correlates Mozscape data with rankings across thousands of actual search results that we use as standards to scale against. While specific metrics like MozRank can answer questions of raw link popularity (i.e. link equity), and link counts can show the raw quantities of linking pages/sites, Domain Authority (and Page Authority) metrics address the higher level question of a domain (or page's) "rankability." Since Authority is based on machine learning calculations, your site's score will often fluctuate as more, less, or different data points are used in the calculation — for instance, when a new Mozscape web index is released. For this reason, keep in mind that it's best to use Domain Authority as a relative metric to compare against the link profiles of other sites as opposed to an absolute value "scoring" the efficacy of your internal SEO efforts.