Domain Authority is a score from 1 to 100 developed by Moz to predict how likely a website is to rank in search results. It is calculated from the number and quality of inbound links pointing to the domain. DA is a third-party metric — Google does not use it, does not recognise it, and has no equivalent internal score that is publicly visible. Despite this, DA remains one of the most commonly reported metrics in SEO. This guide explains what it actually measures, where it is still useful, and which metrics matter more.
What Domain Authority Actually Is
Moz created Domain Authority in 2004 as a way to estimate how authoritative a domain is based on its link profile. The score runs from 1 to 100 on a logarithmic scale — meaning it is relatively easy to move from DA 20 to DA 30, but very difficult to move from DA 70 to DA 80. The score is updated periodically when Moz recrawls the web, so it can change even without any changes to the site being measured.
The calculation factors in the number of unique referring domains (sites linking to the domain), the quality and authority of those linking domains, and the total link count. A site with 500 links from 10 high-authority domains will typically score higher than a site with 500 links from 500 low-authority domains. This reflects the principle that link quality matters more than quantity.
Other SEO platforms have equivalent metrics under different names. Ahrefs uses Domain Rating (DR), Semrush uses Authority Score, and Majestic uses Trust Flow and Citation Flow. None of these are Google metrics. They are each different companies' attempts to estimate what Google might value in a link profile, based on publicly observable link data.
What Google Actually Uses Instead
Google's approach to link authority is based on PageRank — the original algorithm co-developed by Larry Page and Sergey Brin. PageRank distributes link equity across the web based on which pages link to which other pages, weighted by the authority of the linking page. It is a recursive calculation that considers the entire web graph rather than individual domain scores.
Google does not publish PageRank scores externally. The toolbar PageRank that was visible until 2016 was a simplified, delayed version of the internal score. There is no public-facing equivalent today. When SEOs say a site has "high authority" they are inferring this from third-party scores like DA or DR, not from any data Google has shared.
Beyond PageRank, Google evaluates links based on topical relevance (a link from a relevant industry site carries more weight than a link from an unrelated site), anchor text, the position of the link within the page, and signals that indicate whether the link was earned editorially or placed as part of a link scheme. These nuances are not captured in any single DA-style score.
"Domain Authority is a useful proxy for link quality, but it is not what Google uses. Confusing the two leads to optimising for the wrong thing."
Where DA Is Still Useful
DA is most useful as a relative comparison tool — comparing a site's link profile strength against competitors, or assessing the quality of a prospective link partner. If a potential linking domain has DA 50 and your site has DA 20, the link is likely to be more valuable than a link from a DA 10 site, all else being equal.
For link prospecting, filtering by DA is a reasonable starting point for identifying high-authority sites worth targeting. For competitive analysis, comparing DA across the sites ranking for a target keyword gives a rough indication of the link authority bar you need to compete. And for client reporting, DA is a familiar number that tracks directional progress over time in a way clients can understand.
The problem is when DA becomes a target rather than a proxy. Link campaigns that chase DA by acquiring links from high-DA sites regardless of relevance, or that treat DA improvement as the goal rather than ranking improvement, miss the point. A DA 70 link from a completely irrelevant domain will do less for rankings than a DA 30 link from a directly relevant industry site.
What Metrics Actually Matter for SEO Performance
If DA is a proxy and not a direct ranking input, the question is what to measure instead. For link quality, the most useful metrics are:
- Topical relevance: Does the linking site cover related topics? A plumbing business getting a link from a home improvement site is more valuable than the same link from a generic business directory.
- Traffic: Does the linking site actually receive organic search traffic? Sites with strong real traffic tend to have earned it through legitimate content, which correlates with genuine link value.
- Referring domain count trends: Is the number of unique domains linking to a site growing over time? Consistent growth in referring domains is a positive link signal regardless of the DA of any individual link.
- Editorial quality: Is the link placed naturally within relevant content, or is it a footer link, sidebar link, or sitewide link? Editorially placed in-content links carry more weight.
For overall SEO performance, Google Search Console data — impressions, clicks, and average position for target keywords — is the most direct measure of how Google is responding to the site. This is actual ranking data, not a prediction.
Should Agencies Still Report DA to Clients?
DA reporting is not wrong if it is contextualised correctly. Reporting DA alongside actual ranking movements, traffic data, and referring domain growth gives clients a dashboard that shows both proxy indicators and real outcomes. The risk is reporting DA in isolation, which can mask poor actual performance (a site whose DA rises due to low-quality link building while rankings stagnate).
The cleaner approach is to use DR or DA for internal link prospecting, report referring domain growth and quality to clients as the link-building metric, and use Search Console data as the primary performance indicator. This avoids attaching campaign success to a metric that Google ignores.
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