Domain authority is a score that estimates how strong a website’s link profile is. Moz developed Domain Authority and introduced the abbreviation DA; its score runs from 1 to 100. Moz states that DA is not a Google ranking factor. Ahrefs calls its version Domain Rating (DR), Semrush calls its version Authority Score, and other tools have their own. These are scores from SEO tools, and Google does not publish them.
How are the scores calculated?
Each vendor computes the score from its own backlink index. Ahrefs describes the steps for DR. It counts the unique domains linking to a site, looks at the authority of those domains and at how many sites each of them links to, and puts the result on a scale up to 100. Semrush says Authority Score combines link power, estimated organic traffic and spam signals. Because indexes and formulas differ, the same site gets different values in different tools.
What does Google say?
Ahrefs writes that Google representatives have repeatedly said they do not use “domain authority” as a ranking factor, and quotes John Mueller saying Google has a sitewide score that maps to similar things. Semrush states that its Authority Score is not an official metric of Google or other search engines. For practical work, DA, DR and Authority Score are estimates.
How do SEOs use them?
- To compare link strength with competitors, using the same tool each time
- To pre-screen potential link sources
- To follow the development of your own link profile over time
A single value says little about how one page will rank (assessment).
Example
A trade blog shows DR 62 in a tool and links to a vendor’s page. The tool treats that as a link from a strong domain. Whether Google weighs the same link the same way is not known.
FAQ
Is domain authority a Google ranking factor? According to statements quoted by Ahrefs, Google does not use it.
What is a good DA or DR? There is no fixed threshold. A score only helps in comparison with other sites in the same tool.
Sources
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