MOZ Domain Authority (DA) is a search engine ranking score developed by Moz that predicts how likely a website is to rank on search engine result pages (SERPs). A MOZ Domain Authority score ranges from one to 100, with higher scores corresponding to a greater ability to rank.
MOZ Domain Authority is calculated by evaluating multiple factors, including linking root domains and the number of total links, into a single DA score. This score can then be used when comparing websites or tracking the “ranking strength” of a website over time. MOZ Domain Authority is not a metric used by Google in determining search rankings and has no effect on the SERPs.
How Can You Check Domain Authority?
You can check MOZ Domain Authority using Moz’s Link Explorer, the MozBar (Moz’s free SEO toolbar), or in the SERP Analysis section of Keyword Explorer. MOZ Domain Authority metrics are also incorporated into all Moz Pro campaigns, as well as the Moz API.
MOZ Domain Authority metrics are incorporated into dozens of SEO and online marketing platforms across the web.
What is a “good” Domain Authority?
Generally speaking, sites with a very large number of high-quality external links (such as Wikipedia or Google.com) are at the top end of the MOZ Domain Authority scale, whereas small businesses and websites with fewer inbound links may have a much lower DA score. Brand-new websites will always start with a MOZ Domain Authority score of one.
Because MOZ Domain Authority is meant to be a predictor of a site’s ranking ability, having a very high Domain Authority score shouldn’t be your only goal. Look at the DA scores for the sites you’re directly competing with in the SERPs and aim to have a higher score than your competitors. 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” MOZ Domain Authority score.
Technical definition of MOZ Domain Authority
MOZ Domain Authority is based on data from our Link Explorer web index and uses dozens of factors in its calculations. The actual MOZ Domain Authority calculation itself uses a machine learning model to predictively find a “best fit” algorithm that most closely correlates our link data with rankings across thousands of actual search results that we use as standards to scale against.
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, if Facebook were to acquire a billion new links, everyone’s PA and DA would drop relative to Facebook. For this reason, keep in mind that you should always use MOZ 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.
Why did my Authority change?
Because MOZ Domain Authority (and, for that matter, Moz Page Authority ) is comprised of multiple metrics and calculations, pinpointing the exact cause of a change can be a challenge. If your score has gone up or down, there are many potential influencing factors including things like:
Your link profile growth hasn’t yet been captured in our web index.
The highest-authority sites experienced substantial link growth, skewing the scaling process.
You earned links from places that don’t contribute to Google ranking.
We crawled (and included in our index) more or fewer of your linking domains than we had previously.
Your Domain Authority is on the lower end of the scoring spectrum and is thus more impacted by scaling fluctuation.
The key to understanding Page and Domain Authority fluctuations is that these metrics don’t exist in a vacuum — they depend on many positive and negative factors so that even if a given site improves its SEO, its Authority score(s) may not always reflect it. A good metaphor to help understand why is how “best of” rankings work.