What is Domain Authority?

Domain authority is a third-party metric (created by Moz) that predicts how likely a website is to rank in search results, scored from 1 to 100 based on the quality and quantity of backlinks pointing to the domain.

An important caveat is that this is not an official Google metric. Google does not use domain authority or similar scores like Domain Rating within its own algorithms. This distinction matters because a site can have a high third-party score while failing to rank for its target keywords. Clients should interpret this number as a useful proxy for relative strength rather than an absolute rule of search performance. Many SEOs use this score to quickly vet the potential of a link prospect or to gauge the competitive landscape of a new niche. It is essentially a measurement of the "ranking potential" of a whole site based on its link ecosystem.

The score reflects several specific data points regarding your link profile. These include the total count of unique referring domains, the perceived quality of those linking sites, and the diversity of the anchor text used to link to you. A domain with links from established news organisations and academic institutions will generally have a higher score than one with thousands of links from low-quality directories. It is a measurement of your digital reputation as seen through the lens of external citations. The "velocity" of your link acquisition also plays a role in how these third-party tools calculate your growth and stability over time.

A high score does not guarantee ranking success because topical relevance is equally important. A link from a high-authority fitness site may do very little for a law firm because there is no semantic connection between the two brands. This is why a high Domain Rating link sometimes leads to no movement in rankings. Contextual authority is often more powerful than a high generic score from an irrelevant source. In the era of AI search, "niche authority"—being highly relevant to a narrow topic—is often more valuable than a high generic DA score across unrelated subjects.

Practically, you should use domain authority as a comparative benchmark against your direct rivals. If your competitors all have scores in the fifties and you are at twenty, you know you have an authority gap to close. Similar metrics include Ahrefs Domain Rating and Semrush Authority Score. While they use different calculations, they all aim to quantify the same concept of search power. Monitoring your DA over time can help you track the long-term impact of your link building fundamentals efforts. However, always prioritize building "E-E-A-T" (Experience, Expertise, Authoritativeness, and Trustworthiness) rather than just chasing a number on a dashboard.