Domain Authority

Domain Authority® (DA) is a search engine ranking score developed by Moz that predicts how likely a website is to rank in search engine result pages (SERPs). Domain Authority scores range from one to 100, with higher scores corresponding to a greater likelihood of ranking.

Domain Authority is based on data from our robust Link Explorer web index and uses dozens of factors in its calculations. The actual Domain Authority calculation itself uses a machine learning model to predictively find a "best fit" algorithm that most closely correlates our link data with rankings across thousands of actual search results that we use as standards to scale against.

Depending on your requirements, you can check Moz Domain Authority using a range of free or paid tools and API solutions.

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• Start pulling DA in bulk

Get Domain Authority for free

If you're just starting out, the quickest way to check any website's Domain Authority is to use Moz's Link Explorer. You need a free Moz Community account, which gives you access to a range of free tools.

To scope out link data and proprietary moz metrics free while you surf the web. You can download and use MozBar, Moz's free SEO toolbar, to see Domain Authority number of backlinks, amount of link root domains, and other key link metrics.

Domain Authority metrics are also incorporated into all Moz Pro campaigns so you can see how you're performing and better understand where you need to improve and track results over time.

Understanding how Domain Authority impacts your SEO decisions is important. Moz Pro provides high-level metrics in the SERP Analysis section of Keyword Explorer. So you will know how likely you are to compete in the search results.

To find your Domain Authority, head to Link Explorer and start searching. If required, you'll be prompted to create a free Moz Community account or log in to your existing Moz account to access 10 free searches/mo.

Once you've signed up, you can explore backlink data for your website and your competitor's website, including:

• Monitor Domain Authority, Page Authority, and your Linking Domains count over time with easy-to-use graphs
• Viewing lost and discovered linking domains
• See out who is linking to your competitors but not to you
• Finding broken backlinks so you can create a plan for fixing them and much more!

But for the real show-stopper, you can access link metrics, authority metrics, and much more with the Moz API.

Whether you are building a solution for tracking your clients' performance, enjoying creating clever solutions or looking for ways to integrate SEO into a broader digital marketing strategy, we've got the data to get you started with free starter access and affordable plans.

Domain Authority is calculated by evaluating multiple factors, including linking root domains and the total number of links, into a single DA score. This score can then be used when comparing websites or tracking the "ranking strength" of a website over time. Domain Authority is not a Google ranking factor and has no effect on the SERPs.

As of the Domain Authority 2.0 update in early 2019, the calculation of a domain's DA score comes from a machine learning algorithm’s predictions about how often Google is using that domain in its search results. If domain A is more likely to appear in a Google SERP than domain B is, then we would expect domain A's DA to be higher than domain B's DA. Learn more about the Domain Authority update and how to discuss it with your team with this presentation, or explore how to use DA 2.0 metrics with this comprehensive whitepaper.

Since DA is based on machine learning calculations, your site's score will often fluctuate as more, fewer, or different data points become available and are incorporated into those calculations. For instance, if facebook.com were to acquire a billion new links, every other site’s DA would drop relative to Facebook’s. Because more established and authoritative domains like Facebook will have increasingly larger link profiles, they take up more of the high-DA slots, leaving less room at the higher end of the scale for other domains with less robust link profiles. Therefore, it's significantly easier to grow your score from 20 to 30 than it is to grow it from 70 to 80. For this reason, it’s important to use Domain Authority as a comparative metric rather than an absolute one.

This is a very common question in the SEO industry. As with any SEO metrics, the first thing you'll want to understand: "is a Domain Authority of 30 any good? Or could be better?" And as with every SEO question there is a suitable SEO answer: it depends. There isn't really a single specific number you want to achieve, so being realistic and setting achievable goals based on your resources, your competitors, and specific rankings objectives can help you grow your authority in a sustainable way.

A brand-new website will always start with a Domain Authority score of one, and that score will increase as the site earns more and more authoritative backlinks over time.

Remember that sites with very large numbers of high-quality external links will have a higher Domain Authority, whereas small businesses and websites with fewer inbound links may have much lower DA scores. Exploring Moz's list of the top 500 sites on the web can help you understand the impact that Domain Authority and other link-based metrics have on a site's rankings and popularity.

Because Domain Authority is a predictor of a site's ability to rank within its unique competitive landscape, you shouldn’t choose your target DA in a vacuum. Look at the DA scores for the sites you compete with directly in the SERPs and aim for a higher score than your competitors. DA is best used as a comparative metric when investigating the sites within your target SERPs that may have more powerful link profiles than you do — your true competitors. Because the metric is relative, there is no such thing as an absolutely "good," "average," or "bad" Domain Authority score; there are only scores that are "good," "average," or "bad" within the context of a particular competitive landscape.

The best way to influence the Domain Authority metric is to improve your site’s overall SEO health, with a particular focus on the quality and quantity of external links pointing to your site.

Because Domain Authority aggregates so many pieces of data, it can be difficult to influence directly. This metric is meant to predict how competitive a given site will be in Google search results, and since Google considers so many ranking factors in determining its rankings, a metric that tries to approximate its determinations must incorporate a similar number and complexity of factors.

According to Moz's Senior Search Scientist, Tom Capper, the Google 2024 API leak revealed that links are more important than ever and certainly should not be ignored.

Using links to approximate the popularity of pages was a big part of the original Google algorithm, and whilst a lot has changed since, we can see this is still a vital component today. Not only does Google say so themselves and many SEOs confirm from experience, but we can also see the 2024 Google leaks littered with references to link-based features like "homepagePagerank" and "siteAuthority." Our goal is to show you as closely as possible how links to your site or sites might appear to search engines, and provide clear and trusted metrics with which to interpret this wealth of data.

- TOM CAPPER, SENIOR SEARCH SCIENTIST AT MOZ

In Link Explorer, enter any website and scroll down to Metrics over time to see any changes to that site's Domain Authority over the last 12 months.

Because Domain Authority comprises multiple metrics and calculations, pinpointing the exact cause of a change can be a challenge. If your score has gone up or down, there are many potential influencing factors, including things like:

• Your link profile growth hasn't yet been captured in our web index.
• The highest-authority sites experienced substantial link growth, skewing the scaling process.
• You earned links from places that don't contribute to Google rankings.
• We crawled (and included in our index) more or fewer of your linking domains than we had in a previous crawl.
• Your Domain Authority is on the lower end of the scoring spectrum and is thus more impacted by scaling fluctuations.
• Your site was affected by the 2019 implementation of Domain Authority 2.0, which caused a 6% average decrease in DA across all websites due to restructuring and improvements to the way DA is calculated.

The key to understanding Domain Authority fluctuations is recognizing that each domain’s score depends on comparison to other domains all across the DA scale, so that even if a website improves its SEO, its Authority score may not always reflect that. Let's look at how "best of" rankings work as a theoretical illustration:

If Singapore has the best air quality in 2020, and then improves it even further in 2021, are they guaranteed to remain at #1 on the best air quality list? What if Denmark also improves its air quality, or what if New Zealand joins the rating system with extremely high air quality in 2021 after having been left out of the rankings in 2020? Maybe the countries ranking 2–10 all improved dramatically, and Singapore fell to #11 even though their air got better during that time. Because the scale itself has changed, Singapore's ranking could change independently of any action (or inaction) on its part.

Domain Authority works in a similar fashion. Since it’s based on machine learning and constantly compared against every other website on the scale, after each update, recalculations mean that the score of a given site could go down even if that site has improved its link profile. Such is the nature of a relative, scaled system. Therefore — and this is important enough that we'll emphasize it once more — Authority scores are best viewed as comparative rather than absolute metrics.

Page Authority, Domain Authority, and Brand Authority™ are the three main types of authority scores in SEO. They help tell the complete story of your website's ranking capabilities and online reach.

Whereas Domain Authority measures the predictive ranking strength of entire domains or subdomains, Page Authority measures the strength of individual pages.

Updated by Jo Cameron, July 24, 2024

Keep learning

• The Moz Blog, Q&A forum, and webinar introducing Domain Authority 2.0
• How to Use Domain Authority 2.0 for SEO — Whiteboard Friday
• The top 500 sites on the web, organized by Domain Authority
• Page Authority
• External Links
• Discover your true SEO competitors with this feature in Moz Pro