Domain Authority

Domain Authority (DA) is a third-party metric originally developed by Moz that predicts the likelihood of a domain ranking in search results on a logarithmic scale from 0 to 100. Because the scale is logarithmic, climbing from 20 to 30 is roughly an order of magnitude easier than moving from 70 to 80 — the top of the distribution is exponentially thinner.

DA is calculated from the link graph: the quantity, quality, and topical relevance of referring domains pointing to a site, together with signals about those referring domains themselves. It is not a Google ranking factor. Google has stated this publicly and repeatedly. DA is, however, a useful proxy for the link-graph strength that does feed Google's own algorithms, which is why operators continue to track it.

Treat DA as a relative benchmark, not a target. Comparing your DA against direct competitors in the same SERP is meaningful. Comparing a niche affiliate site's DA against Wikipedia's is not. The metric is also sensitive to data refreshes — periodic recalibrations by Moz can cause every site in an index to drop or rise simultaneously, which has nothing to do with the site's actual performance.

Different vendors publish their own authority scores. Ahrefs has Domain Rating, Majestic has Trust Flow and Citation Flow, Semrush has Authority Score. They correlate with each other but rarely match digit-for-digit because the underlying crawl footprints and weighting models differ.

Tools like SEOlvl track Authority Score daily so operators can see drift, recovery, and the impact of campaigns over time rather than relying on quarterly check-ins. Sudden moves of more than three or four points usually trace back to either a vendor index refresh, a Lost Backlink from a high-authority referring domain, or a recently acquired high-quality link that has just been indexed.

To raise DA in practice: earn editorial links from topically relevant, high-authority sites; clean up Toxic Backlink patterns; and consolidate redirects so equity flows to your canonical hostname.