Domain authority explained: what it is and how to improve your score

What domain authority actually measures

Domain authority is a score that estimates how well a website is likely to rank in search results based on the strength and quality of its backlink profile. The term was popularised by Moz, which called its version Domain Authority. Ahrefs calls its equivalent metric Domain Rating. Semrush uses the term Authority Score. Each one measures something slightly different, but all three are built on the same foundation: the number and quality of external websites linking to a domain.

None of these scores is a Google metric. Google does not use domain authority, Domain Rating, or Authority Score in its ranking algorithm. These are third-party approximations, built by SEO tool companies to model the relationship between backlink strength and search performance. They are useful for benchmarking and for tracking the effect of link building activity over time, but they are not a direct measure of how well any specific page will rank.

Domain authority scores are calculated on a logarithmic scale in most implementations, which means moving from 20 to 30 is considerably easier than moving from 60 to 70. The higher the score, the more high-quality referring domains are required to produce each incremental gain. This is why large, established sites with thousands of referring domains improve slowly despite active link building programmes.

The most useful application of a domain authority checker is comparative. Checking your own score in isolation tells you little. Checking your score alongside your five closest organic competitors tells you whether your backlink profile is strong enough to compete for the keywords you are targeting, or whether you have a meaningful authority gap to close before rankings will move. For a full picture of your site's SEO health beyond authority alone, the website SEO health check guide covers every layer of the audit in sequence.

How different tools calculate authority scores

The three main authority metrics use different data and methodologies, which is why the same domain can score 45 in one tool and 62 in another. Understanding what each tool measures helps you choose which score to use as your benchmark and interpret changes correctly.

Ahrefs Domain Rating

Ahrefs Domain Rating is calculated using Ahrefs' own backlink index, which is updated continuously and is one of the largest in the industry. The score reflects the strength of a domain's backlink profile relative to all other domains in the Ahrefs index. A Domain Rating of 50 means the domain has a stronger backlink profile than roughly the bottom 50% of all indexed domains. The metric factors in the number of unique referring domains, the Domain Rating of those referring domains, and the number of other domains each referring domain links to, reducing the value of links from domains that link to hundreds of thousands of sites. Explore Ahrefs at Ahrefs.

Semrush Authority Score

Semrush Authority Score uses a broader set of inputs than a pure backlink metric. It incorporates backlink data from Semrush's index, organic search traffic estimates, and spam signals to produce a composite score out of 100. This makes the Semrush score more sensitive to changes in a site's organic performance as well as its link profile, which means a site that gains traffic without gaining links can still see its Authority Score rise. The platform provides Authority Score data for any domain through its Backlink Analytics report. Explore Semrush at Semrush.

Moz Domain Authority

Moz Domain Authority is the original version of the metric and remains widely cited, particularly in agency reporting. It uses Moz's Link Explorer index and is scored against a machine learning model trained to correlate with Google rankings. Moz updates its metric periodically in bulk rather than continuously, which means scores can shift significantly after a Moz index update even if your backlink profile has not changed materially. The free Moz Link Explorer tool provides Domain Authority lookups without a subscription.

What a good domain authority score looks like

There is no universally good domain authority score because the metric is relative. A score of 35 in a niche where all competitors score between 20 and 45 is entirely competitive. A score of 35 in a niche dominated by national news sites and large e-commerce platforms scoring 75 to 90 indicates a very large authority gap that content and technical fixes alone will not close.

As a rough reference frame across industries:

• Brand new domains with no backlinks: 0 to 10
• Small local businesses and early-stage startups after their first year: 10 to 25
• Established small businesses and specialist blogs with consistent link building: 25 to 45
• Recognised industry publications, well-funded startups, and established SaaS platforms: 45 to 65
• Major national brands, large news outlets, and category-leading platforms: 65 to 90+

These ranges are indicative rather than definitive, and they vary by tool because Ahrefs, Semrush, and Moz all calibrate their scores differently. The only comparison that matters for practical SEO decisions is your score versus the scores of the pages currently ranking in the top five for your target keywords.

How to improve your domain authority

Domain authority is driven almost entirely by your backlink profile. The technical and on-page work you do improves your rankings by removing barriers, but it does not move your authority score unless it results in more websites linking to you. The following approaches are the most reliable ways to earn new referring domains.

Earn links through original content

Content that contains original data, research findings, or unique analysis earns links because other sites need a source to cite. A survey of your existing customers, an analysis of publicly available industry data, or an original benchmark report gives journalists, bloggers, and industry publications a reason to link. This type of content requires effort to produce but earns links passively over time rather than requiring outreach for each individual link.

Build relationships with relevant publications

Guest posting on reputable sites in your sector remains one of the most controllable link acquisition methods. The quality of the publication matters more than the quantity of posts. One link from a respected industry publication with a Domain Rating of 60 contributes more to your authority than ten links from generic blogs at Domain Rating 20. Focus on sites whose audience overlaps with yours and where editorial standards are high enough to make the placement meaningful.

Reclaim unlinked brand mentions

Tools like Ahrefs and Semrush can identify pages that mention your brand name without linking to you. These are warm link prospects because the author already knows and has written about your business. A short, direct outreach email asking whether they would be willing to add a link converts at a higher rate than cold outreach because the relationship and context already exist.

Fix broken backlinks

If external sites link to pages on your domain that no longer exist, those links are currently passing no authority. Identify 404 pages with backlinks using Ahrefs Site Explorer's broken backlinks report and add 301 redirects from the old URLs to the most relevant current pages. This recovers link equity that has already been earned without any additional outreach.

Register your domain correctly

Domain registration has no direct effect on authority scores, but starting with a strong domain name from a reputable registrar sets a clean foundation. Services like Namecheap and GoDaddy offer domain registration with privacy protection, which prevents your contact details from appearing in WHOIS lookups and reduces spam outreach. If you are building a new site specifically to target a competitive keyword cluster, buying an aged domain with an existing backlink profile is a shortcut that some practitioners use, though the quality of the inherited links requires careful vetting before using the domain.

Domain authority vs page authority: the difference

Domain authority measures the overall backlink strength of an entire domain. Page authority measures the backlink strength of a single URL. Both metrics exist in most SEO tools under different names — Ahrefs calls the page-level metric URL Rating, Moz calls it Page Authority, and Semrush reports it within its Backlink Analytics tool.

The practical difference matters for keyword targeting. A domain with moderate overall authority can rank a specific page for a competitive keyword if that page has accumulated strong backlinks pointing directly to it. Conversely, a high domain authority does not guarantee that every page on the domain will rank, individual pages still need their own backlink profile and on-page optimisation to compete.

For most SEO practitioners, domain authority is the metric used for prospecting and competitive benchmarking, while page authority is used when evaluating whether a specific piece of content is likely to rank for a specific keyword. Both are approximations, and both should be read alongside the actual search results for the target keyword rather than in isolation.

What this means for your link building strategy

Your domain authority score tells you where your backlink profile sits relative to your competitors. The gap between your score and the scores of the pages ranking above you gives you a rough sense of how much link building is required before authority stops being the limiting factor in your rankings.

A large authority gap, say 20 or more points below the top-ranking competitors, suggests that content quality and technical fixes will have limited impact until the link gap is closed. A small authority gap, say five or fewer points, suggests that on-page optimisation, content depth, and keyword targeting are more likely to be the deciding factors. The website SEO health check approach, auditing technical health, on-page signals, and backlinks together, gives you the full picture rather than optimising one dimension while another is the actual bottleneck.

Track your Domain Rating or Authority Score monthly using the same tool consistently. Switching between tools mid-campaign makes trend data unreliable because each tool calibrates its scores differently. Set a starting baseline, define a target score based on your top competitors, and measure progress against that target rather than chasing an abstract number.

For sites where link building is the primary growth lever, combining domain authority tracking with a full website SEO health check every quarter ensures that technical issues are not silently limiting the impact of the links you are earning. A site with strong authority but significant crawl errors will underperform its link profile because Google cannot fully index the pages those links are pointing to.

If you are building domain authority as part of a wider SEO programme and need to understand how your authority compares to competitors in detail, the SEO competitor analysis guide covers how to benchmark authority, content, and traffic data against the specific domains you are competing with.