Domain Authority (DA) is a number between 1 and 100 that estimates how well a website might rank in search results.
Domain Authority is an approximate value that expresses a website’s estimated ranking strength as a number. It attempts to estimate how the site might perform in search engine results pages (SERPs), based largely on various metrics from the backlink profile.
Domain Authority was developed by the analytics provider Moz; Google itself does not use it for ranking. The estimated value is a helpful guide, but it is not an official metric.
The term was coined by the SEO company Moz, which uses Domain Authority as its own metric to estimate a domain’s ranking potential using link data and a machine-learning model.
Google has not released a public metric for the strength of individual websites for years. Other analytics providers followed suit with their own similar metrics, which is why there are now several competing authority scores that attempt to assess a domain’s strength in different ways.
Domain Authority provides a rough benchmark and helps assess how your own website stacks up against the competition. It also shows how strong other websites are from which you hope to gain backlinks.
DA thus serves as a guide, but it does not replace more in-depth analyses.
The number is merely an estimate—nothing more, nothing less. It does not come from Google and does not directly influence search rankings.
Countless providers have their own authority scores, which makes them only partially comparable with one another. Domain Authority focuses heavily on the backlink profile in its evaluation and does not directly reflect many other factors that may be relevant to actual Google rankings.
A company is reviewing industry portals where it could publish a guest post and thereby obtain a valuable backlink. Portal A has a significantly higher Domain Authority than Portal B.
At first glance, this rough assessment suggests that Portal A might be the stronger link source. However, the number does not replace the need to verify whether the portal is thematically relevant and has an actual readership.