“Domain authority” is shorthand for one question: how strong is this website in the eyes of search engines? Several companies have built metrics to answer it, each with its own name and formula. None of them is used by Google, but they are useful to compare websites and to evaluate links.
PageRank: where it all started
PageRank was the original algorithm behind Google: a page is important if important pages link to it. Google still uses evolved versions of it internally, but it stopped showing public PageRank scores in 2016. All the metrics below are third-party attempts to estimate something similar.
Moz Domain Authority (DA)
A score from 1 to 100 that predicts how likely a domain is to rank, based on Moz’s link index and a machine learning model. It is logarithmic: going from 20 to 30 is much easier than going from 70 to 80. Moz also has Page Authority (PA) for individual URLs.
Ahrefs Domain Rating (DR)
A score from 0 to 100 that measures the strength of a site’s backlink profile, based on how many unique domains link to it and how strong those domains are. It looks only at links, not at traffic.
Semrush Authority Score (AS)
A score from 0 to 100 that combines backlink data with organic traffic estimates and spam signals. Because it includes traffic, sites with strong rankings but few links can score higher than in link-only metrics.
Majestic Trust Flow and Citation Flow
Majestic splits authority in two: Citation Flow measures how many links point to a site, and Trust Flow measures how close those links are to a set of trusted seed sites. A big gap between the two can be a sign of low-quality links.
Open data alternatives
Open PageRank calculates a PageRank-style score from the Common Crawl link graph, and the Tranco list ranks the top 1 million domains by combining several popularity sources. Our free Domain Authority Checker combines both with the domain’s age into a single 0 to 100 estimate built only from open data.
What is a good domain authority score?
There is no universal good score. What matters is your score relative to the sites you compete with. A local bakery with a score of 20 can dominate local searches, while a national media site with 60 may struggle in a niche full of 80s. Compare yourself with the pages that rank for your target keywords.
How to increase domain authority
- Publish content others want to cite: original data, research, tools and in-depth guides.
- Get mentioned by media, associations and partners in your industry.
- Reclaim unlinked brand mentions and broken links that pointed to your site.
- Fix internal linking so authority flows to your important pages.
- Be patient: these scores move slowly and are updated in cycles.
Learn how to check backlinks for free to see where your authority comes from.
Frequently asked questions
Does Google use Domain Authority?
No. Google has said many times that it does not use Moz DA or any other third-party authority score.
Why did my domain authority drop?
Usually because the tool updated its index or model, or because you lost links. A drop across all competitors at the same time points to a tool update.
Which metric is the best?
None is objectively better. Pick one, use it consistently, and focus on comparisons rather than absolute numbers.