What is Domain Authority?
Domain Authority is a score created by the software company Moz that predicts how likely a website is to rank in search results. It runs from 1 to 100, and a higher score indicates a stronger predicted ability to rank relative to other sites.
The most important fact about it is the one most often missed: it is a third-party estimate, not a search engine’s own measure. Google does not calculate Domain Authority, does not receive it, and does not use it to rank anything. Other tools publish their own competing scores under similar names, each with its own method and its own numbers.
It remains useful when read as what it is: a comparative estimate, based largely on a site’s link profile, that helps judge relative strength between sites. It becomes misleading the moment it is treated as a grade a search engine has awarded.
Key Takeaways
- It is a third-party prediction, not a ranking factor. No search engine uses it.
- The scale is logarithmic, so moving from 20 to 30 is far easier than moving from 70 to 80.
- It is comparative. A score is meaningful only against the scores of the sites competing for the same queries.
- It can move without anything changing on the site, because it is recalculated as the index behind it changes.
Formula (If Applicable)
Moz does not publish an exact formula. The score is produced by a machine learning model trained to predict rankings, using inputs drawn from the link graph, principally the number of distinct domains linking to a site and the strength of those linking domains, combined into a single figure.
Two properties of the scale matter in practice. It is logarithmic, so each additional point costs progressively more effort than the last, and a site moving from a low score to a moderate one has done far less work than a site moving from a high score to a slightly higher one. And it is relative: the score is calibrated against the rest of the index, so a site can lose points because other sites gained them, without having lost anything itself.
Real-World Example
A business is told its Domain Authority is 18 and that a competitor’s is 42, and concludes that it cannot compete. The conclusion does not follow. Domain Authority estimates strength across a whole domain, while ranking happens page by page against a specific query. A focused page answering a specific question, on a site with a modest score, routinely outranks a broad page on a stronger site when it answers the question better.
The score is best used to set expectations rather than to make decisions. It indicates roughly how much competitive weight a site carries, which informs whether to pursue a highly contested term now or build toward it.
Importance in Business or Economics
Used properly, the score is a planning input. Comparing a site against the specific competitors ranking for a valuable query gives a rough sense of whether that query is reachable in the near term or is a longer project, which affects where effort is spent.
Used improperly, it distorts spending. Treating the number as a target encourages buying links to move it, which risks a penalty from the search engines that never used the score in the first place. The score is a symptom of a healthy link profile, not a cause of one, and pursuing the symptom directly is how businesses damage the thing being measured.
Types or Variations
- Domain Authority: Moz’s site-level score, from 1 to 100.
- Page Authority: Moz’s equivalent score for an individual page rather than a whole site.
- Competing vendor scores: other SEO tools publish their own site-strength metrics, calculated differently and not interchangeable with Moz’s.
- PageRank: Google’s own historical link-based measure, which has not been publicly visible for many years and should not be confused with any vendor score.
Frequently Asked Questions (FAQs)
Does Google use Domain Authority?
No. It is a metric created by Moz, a third-party software company. Google has stated repeatedly that it has no such site-wide authority score, and it does not receive or use Moz’s.
What is a good Domain Authority score?
There is no absolute threshold, because the scale is relative and logarithmic. The only useful comparison is against the sites currently ranking for the queries you want, in your own market.
Why did the score fall when nothing changed on the site?
It is recalculated against the whole index. If other sites gain links, or the underlying crawl changes, a site can lose points without losing anything itself. Treat movement as noise unless it persists.
Related Terms
- Authority Signals
- Search Engine Optimization (SEO)
- Keyword Ranking
- Organic Traffic
- Search Engine Results Page (SERP)
Sources and Further Reading
- Moz. Domain Authority. moz.com
- Google Search Central. Creating Helpful, Reliable, People-First Content. developers.google.com