What is domain authority?
Moz Domain Authority (also called DA score - domain score - Moztrust) is a metric developed to help predict how likely a domain, subdomain, or page is to rank in search engine result pages (SERPS). This website ranking measure is determined on a logarithmic scale and the score ranges from 1 to 100, 1 being where all new websites start and move on up from there.
Although we don't know the exact algorithm, Domain Authority is calculated by looking at multiple important factors, including referring domain, linking root domains, and the total number of links, into a single DA score. Moz has announced that overall SEO website health (on-page optimizations, metadata optimizations, technical SEO improvements) and high authority backlinks have a positive impact on Domain Authority.
Whereas a website's da measures the strength of an entire domain, there is also a DA score attributed to each web page, called page authority.