What Is Domain Authority and How Do You Build It?

Domain Authority is a score from 1 to 100, created by the SEO software company Moz, that predicts how likely a website is to rank in search results compared with its competitors. Moz’s own explanation of Domain Authority is clear that it is a comparative metric and not a Google ranking factor, so a higher score reflects a stronger link profile rather than something Google rewards directly. For organisations investing in SEO services for UK businesses, understanding that distinction is what stops the metric from steering strategy in the wrong direction.

A single number is easy to report on, which is exactly why it gets misread. Treated as a benchmark against competitors it has real value. Treated as a target in its own right it tends to encourage the wrong kind of work. The short version looks like this.

• Domain Authority is a Moz metric based mainly on backlink data.
• It is relative, so your score can move when other websites gain or lose links.
• Google has said repeatedly that it does not use Domain Authority to rank pages.
• Ahrefs Domain Rating and Semrush Authority Score are similar metrics built on different data.
• Authority grows from useful content, digital PR, sound internal linking and good technical health.

Each of those points shapes how the score should be used in reporting and planning. The sections below take them in turn, starting with how the number is produced.

How Domain Authority Is Calculated

Moz calculates Domain Authority with a machine learning model that weighs a range of signals, with backlink data carrying most of the weight. The largest factors are the number of linking root domains (the separate websites that link to you) and the quality of those links, judged by how well they correlate with rankings across a large set of search results.

Breadth matters more than volume. A handful of links from many different websites usually counts for more than a large number of links from one or two. Moz describes referring domains as one of the most important factors in the score. A link from an established publication in your sector carries far more weight than a long list of directory entries or comment links.

The score is relative to every other website in Moz’s index. Moz explains that if a very large platform gained a huge number of new links, other websites would drop relative to it. That design makes it far easier to move a score at the lower end of the scale than near the upper end. Each step up gets harder as the easier opportunities run out and the publications that remain become more selective about what they link to.

That relative design explains why scores move without any change on your side. Your score can rise or fall as your own backlink profile changes, as competitors gain or lose links, or when Moz updates its link index and calculation model. A small drop after an update is rarely a sign that anything has gone wrong, so trends over several months tell you far more than a single reading.

Is Domain Authority a Google Ranking Factor

Domain Authority is not a Google ranking factor. Google has said so many times. Search Engine Journal’s review of the evidence on Domain Authority collects statements from Google’s John Mueller and Gary Illyes over several years, including Mueller’s comment that Google does not use Domain Authority at all in its algorithms.

That does not mean links are irrelevant. Google’s SEO Starter Guide explains that PageRank uses links and is one of the fundamental algorithms at Google, then adds that it is only one of many ranking signals. Mueller has acknowledged that Google holds some signals at a website level which may map onto similar ideas, but those are internal measures that no third party can see or reproduce.

The practical point is that Domain Authority is a model of how a search engine might view your links, built by a company outside Google. It often correlates with rankings, as websites with strong link profiles tend to rank well, but improving the score does not cause better rankings on its own.

How Domain Authority Compares With Other Authority Metrics

Ahrefs and Semrush each publish their own version of the same idea, calculated from their own crawl of the web. Ahrefs describes Domain Rating as a measure of the relative strength of a website’s backlink profile on a logarithmic scale from 0 to 100. Semrush scores Authority Score from 1 to 100 using link power, organic traffic and spam factors.

The three definitions are worth reading side by side. The differences in what each one measures explain why the numbers rarely match for the same website.

Domain Authority

Moz’s comparative score, produced by a machine learning model that relies mainly on linking root domains and link quality. It predicts ranking ability relative to other websites.

Domain Rating

Ahrefs’ measure of backlink profile strength, based on followed links from unique domains. Only the first link from each linking domain counts towards it.

Authority Score

Semrush’s compound metric, combining link power, estimated organic traffic and signs of spam or manipulation. Semrush recommends it for comparing domains rather than judging one in isolation.

Expect each tool to give your website a different number. Each one crawls a different slice of the web, counts links differently and updates on its own schedule, so averaging them creates confusion rather than clarity. Picking one tool and using it consistently for benchmarking is far more useful than switching between them.

What Counts as a Good Domain Authority Score

A good Domain Authority score is one that is competitive with the websites ranking for the searches you care about. Moz states that there is no universal good or average score. By its own account, a score which looks strong in one industry can look weak in another.

New websites start at the bottom of the scale and climb as they earn links, whereas established brands with years of press coverage sit much higher. The useful comparison is with the specific domains you meet in search results, not with household names or a benchmark found online. A specialist B2B firm in a narrow sector can rank well with a modest score when its competitors have similar link profiles.

You can check your score for free through Moz’s Link Explorer, which needs a free Moz account. Run the same check on the competitors who outrank you, then look at what sits behind the gap, such as how many referring domains they have, which publications link to them and which of their pages attract the most links. Our guide to understanding your link profile covers how to read that data.

Why Chasing a Higher Score Backfires

Treating Domain Authority as a target tends to push teams towards the tactics that do the most damage. The quickest ways to add links are buying them, swapping them or placing them on low quality directories. Every one of those appears in Google’s spam policies as link spam.

Google defines link spam as creating links primarily to manipulate search rankings. Its examples include buying or selling links for ranking purposes, excessive link exchanges, automated services that create links and low quality directory or bookmark links. Google states that websites which violate its policies may rank lower or not appear in results at all.

The score can hide real progress too. A link from a respected trade publication in your sector may barely move Domain Authority and still send qualified visitors, strengthen a key service page and build trust with buyers. Each of those outcomes matters more to the business than a small rise in a third party metric.

How to Build Domain Authority Properly

Building domain authority properly means earning links that people choose to give, then making sure your website gets full value from them. Google’s guidance on creating helpful, reliable content says its ranking systems are designed to prioritise content created to benefit people rather than to manipulate rankings. That same content is what other websites want to cite.

The work falls into four stages. Each one supports the next, so skipping the technical groundwork tends to waste the value of links earned later.

Technical health comes first, as broken pages, long redirect chains and orphaned pages all waste link value you have already earned. A technical SEO review usually finds fixes of this kind quickly. The benefit carries through to every link you earn afterwards.

Content and digital PR do the earning. Original research, practical guides and clear expert commentary give journalists and trade editors a reason to link. Most sectors have a small group of publications that regularly reference outside expertise. Our off-page SEO services focus on this kind of strategic link acquisition, with backlink profile analysis and citation management that follow Google’s guidelines.

Internal linking spreads the value of those links across your website. Google’s documentation on crawlable links recommends that every important page has a link from at least one other page on the website and that anchor text describes the destination. Our article on how internal linking strengthens website architecture explains how to structure this so authority reaches the pages that generate enquiries.

Using Authority Metrics Sensibly

Authority metrics are most useful as one input in a wider picture of search performance. Check them quarterly, compare against the competitors you meet in search results and use them to judge which link opportunities are worth pursuing, then put more weight on organic traffic, rankings for commercial queries and the enquiries search generates.

Priority Pixels examines technical architecture, content quality and off-page authority together when auditing a website. Backlink profiles are analysed to find realistic acquisition opportunities. Retainer clients follow progress through our reporting platform, which brings Google Analytics traffic, Search Console rankings and conversion tracking into one place, so authority is always read alongside the results it is meant to support.

Domain Authority will keep appearing in reports and sales pitches. It is a reasonable shorthand for link strength when it is read the way Moz intends. Treat it as a benchmark and earn links that would be worth having if the metric did not exist. The score tends to follow from that work.