What is Domain Authority (DA)? The Definitive Guide to SEO’s Most Famous Metric
In the world of Search Engine Optimization (SEO), few terms carry as much weight, or cause as much confusion, as Domain Authority (DA). If you have ever spent time in an SEO dashboard or sat through a digital marketing presentation, you have likely seen this number—a score from 0 to 100 that seemingly dictates the “strength” of a website.
For some, it is the ultimate North Star for link building. For others, it is a “vanity metric” that distracts from what truly matters. The reality lies somewhere in the middle. Domain Authority is an incredibly useful diagnostic tool, provided you understand what it actually measures—and, perhaps more importantly, what it does not.
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One of the most persistent myths in the industry is that Domain Authority is a metric used by Google to rank websites. This is false. Domain Authority is a third-party metric developed by Moz. While it correlates with higher rankings, it is a predictor, not a cause.
In this comprehensive guide, we will break down the mechanics of Domain Authority, explore how it is calculated, compare it to other industry metrics, and provide a roadmap for how you can use it to grow your organic search presence.
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What is Domain Authority? (Core Definition)
At its simplest, Domain Authority (DA) is a search engine ranking score developed by Moz that predicts how likely a website is to rank on search engine result pages (SERPs).
The 0–100 Scale
Domain Authority is scored on a logarithmic scale from 1 to 100.
1–20: Brand new websites or sites with very few quality backlinks.
20–50: Established sites that are starting to grow their link profile.
50–70: Very strong sites with significant influence in their niche.
70–100: Massive, authoritative sites (e.g., Wikipedia, The New York Times, Google).
Because the scale is logarithmic, it is much easier to grow your score from 10 to 20 than it is to grow it from 70 to 80. As you move up the ladder, each incremental point requires significantly more effort and high-quality link acquisition.
A Comparative, Not Absolute, Metric
It is a mistake to view DA as a grade on a test where “100” is the only goal. Instead, DA is a comparative tool. If you are a local bakery and your primary competitor has a DA of 15, your goal is to reach a DA of 20. You do not need a DA of 90 to dominate your local market.
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History and Background of DA
To understand why Domain Authority exists, we have to look back at the early days of Google.
The Era of PageRank
Originally, Google used a metric called PageRank (named after co-founder Larry Page) to measure the importance of a webpage based on the number and quality of links pointing to it. For many years, PageRank scores were publicly visible via the Google Toolbar. However, this led to an explosion of link spam as webmasters obsessed over “chasing PR.”
In 2016, Google officially retired the public-facing PageRank score. This left SEO professionals in the dark; they no longer had a way to see how Google viewed the “authority” of a site.
The Birth of Moz’s DA
Seeing a gap in the market, Moz developed Domain Authority as a way to reverse-engineer Google’s algorithm. They wanted to provide a proxy metric that would allow marketers to compare the “ranking power” of different domains.
Over the years, the DA algorithm has evolved. In 2019, Moz released “Domain Authority 2.0,” which utilized a more sophisticated machine learning model to better align with the modern complexities of Google’s actual ranking behavior, focusing more on link quality and spam detection than just raw link volume.
How Domain Authority is Calculated
Moz uses a machine learning model to calculate DA by looking at how often Google uses a particular domain in its search results. If Domain A consistently outranks Domain B for various keywords, Domain A will have a higher DA.
To arrive at this number, Moz integrates data from its Link Explorer index. Several key factors influence the final score:
1. Linking Root Domains
This is the number of unique domains linking to your site. Getting ten links from one website is generally less impactful for your DA than getting one link each from ten different websites.
2. Number of Backlinks
The total count of individual pages linking to your site. While “Linking Root Domains” is more important, the total volume still plays a secondary role.
3. Quality of Backlinks
Not all links are created equal. A link from a high-authority, trustworthy site like the BBC carries significantly more weight than a link from an obscure, low-traffic blog.
4. Spam Score
Moz evaluates the “health” of a site’s link profile. If a site is surrounded by “spammy” neighborhoods—low-quality directories, link farms, or irrelevant sites—its DA may be suppressed.
5. Link Equity (MozRank and MozTrust)
Moz also considers how “trustworthy” the linking sites are. Links from government (.gov) or educational (.edu) institutions often carry high trust signals, though Moz does not treat these extensions differently purely based on their TLD; it’s about the authority they have built.
Note: Because DA is based on machine learning against a massive index, your score can fluctuate even if your site hasn’t changed. If a giant site like Facebook acquires millions of new links, it can technically “edge out” smaller sites on the 100-point scale, causing their DA to drop slightly.
DA vs. Google Ranking Factors
It is vital to reiterate: Google does not use Domain Authority as a ranking signal.
When Google’s bots crawl your site, they are looking at:
Content Relevance: Does this page answer the user’s query?
User Experience (Core Web Vitals): Is the site fast and mobile-friendly?
E-E-A-T: Experience, Expertise, Authoritativeness, and Trustworthiness.
On-Page SEO: Are the title tags and headers optimized?
Why DA Still Matters
Even though Google doesn’t use the DA score, the factors that increase your DA (high-quality backlinks, mentions from reputable sources) are the same factors that Google does use to determine rankings. Therefore, a high DA is a strong symptom of a successful SEO strategy, even if it isn’t the cause of it.
What is a “Good” Domain Authority Score?
There is no such thing as a “good” DA in a vacuum. A “good” score is simply one that is higher than your direct competitors.
| Score Range | Classification | Typical Examples |
| 0–20 | Low/New | Brand new blogs, local niche businesses. |
| 20–40 | Average | Growing niche sites, small e-commerce stores. |
| 40–60 | Strong | Well-known industry blogs, mid-sized publishers. |
| 60–80 | Very High | Major national news outlets, huge SaaS companies. |
| 80–100 | Exceptional | Apple, Google, Wikipedia, Amazon. |
The Competitive Context
If you are a personal injury lawyer in a specific city, and your top three competitors have DAs of 18, 22, and 25, then a DA of 30 is “excellent.” You don’t need a DA of 70 to rank #1 in that specific niche.
Domain Authority vs. Page Authority
While Domain Authority measures the strength of the entire domain (including all subdomains), Page Authority (PA) measures the ranking strength of a single, specific page.
DA: Reflects the overall “brand power” and link profile of the whole site.
PA: Reflects the specific link profile of one URL (e.g., a specific blog post or product page).
Practical Example:
A new blog post on The New York Times (High DA) will start with a high “inherited” ranking potential, but its specific PA might be low until it earns its own individual backlinks. Conversely, a viral post on a small blog might have a very high PA even if the site’s overall DA is low.
DA vs. Other SEO Metrics
Moz is not the only company with an authority metric. Other major SEO tools have developed their own versions:
Ahrefs – Domain Rating (DR): Primarily focused on the quantity and quality of “dofollow” backlinks. Many SEOs prefer DR because Ahrefs has a massive, frequently updated backlink index.
SEMrush – Authority Score: A compound metric that looks at backlink data, organic search data, and website traffic data to resist manipulation.
Majestic – Trust Flow (TF) & Citation Flow (CF): TF measures the quality of links (how close you are to trusted “seed” sites), while CF measures the quantity.
While these scores often correlate, they can differ wildly. A site might have a DA of 50 but a DR of 40. This is why it is best to pick one tool and use it consistently for benchmarking rather than mixing metrics from different providers.
How to Check Domain Authority
Checking your DA is straightforward and can be done for free:
Moz Link Explorer: The official tool. You can enter any URL and see its DA, PA, and top linking domains.
MozBar: A free Chrome extension that displays the DA and PA of any site you visit directly in your browser or on the Google SERP.
Third-Party Aggregators: Many free “DA Checker” websites exist, though using the official Moz tool is always the most accurate method.
Why Domain Authority Matters
If Google doesn’t use it, why should you care?
Competitive Analysis: It allows you to see how much “heavy lifting” you need to do to catch up to the leaders in your niche.
Link Prospecting: When looking for sites to guest post on or collaborate with, DA helps you filter out low-quality or “spammy” sites.
Progress Tracking: It is a high-level way to see if your long-term link-building efforts are moving the needle.
Guest Posting ROI: If you spend 10 hours writing a guest post, you want to ensure the site publishing it has enough authority to pass “link juice” back to you.
Limitations of Domain Authority
DA is not perfect. Relying on it too heavily can lead to poor SEO decisions.
Manipulability: It is possible to “inflate” DA using black-hat link-building techniques (like PBNs or link farms). A site might have a DA of 50 but zero actual organic traffic.
No Content Context: DA doesn’t know if your content is well-written or helpful.
Lagging Indicator: It takes time for the Moz index to crawl new links. Your SEO might be improving weeks before your DA score reflects it.
Niche Blindness: It doesn’t account for the fact that a DA 20 site in a tiny niche might be much more valuable than a DA 50 general news site.
How to Improve Domain Authority (Actionable Section)
Improving your DA is a marathon, not a sprint. It involves improving the overall “trust” and “authority” of your site in the eyes of the internet.
1. Build High-Quality Backlinks
The most direct way to increase DA is to earn links from sites that already have high DA.
Guest Posting: Write valuable content for reputable sites in your industry.
Digital PR: Create “link-worthy” assets like original research, data studies, or infographics that journalists want to cite.
The Skyscraper Technique: Find a popular piece of content, create something significantly better, and reach out to those who linked to the original.
2. Improve Content Quality
High-quality content earns links naturally.
Focus on E-E-A-T: Ensure your content is written by experts and provides unique value.
Topic Clusters: Create deep, comprehensive guides on specific subjects to establish topical authority.
3. Technical SEO Optimization
While links are the main driver, a broken site won’t rank well or earn links.
Site Speed: Use tools like PageSpeed Insights to ensure your site loads fast.
Mobile-Friendliness: Ensure your site is fully responsive.
Crawlability: Make sure your robots.txt and sitemap are correctly configured.
4. Internal Linking Strategy
Internal links don’t increase your Domain Authority, but they help distribute the “authority” you earn from external links to your deeper pages (improving Page Authority).
5. Remove Toxic Links
Perform regular link audits. Use the Moz Spam Score or Ahrefs to identify links from “bad neighborhoods.” If your site has been hit by a manual action or is suffering from a “negative SEO” attack, use the Google Disavow tool—though use this with caution, as Google is generally good at ignoring spam on its own.
How Long Does It Take to Increase DA?
Increasing your DA from 10 to 30 can happen in a few months with a concerted effort. However, moving from 50 to 60 can take a year or more. It depends on:
Competition: How fast are others in your niche growing?
Link Velocity: How many new, high-quality links are you earning per month?
Link Quality: One link from a DA 90 site is worth more than 100 links from DA 10 sites.
Common Myths About Domain Authority
“Higher DA guarantees rankings”
False. A DA 40 site can easily outrank a DA 60 site if the DA 40 site has better content, better user intent match, and better on-page SEO for that specific keyword.
“DA increases instantly”
False. Moz updates its index every few weeks. Even after a major link is earned, it can take one or two update cycles to see a change in your score.
“You should only chase high DA links”
False. A “natural” link profile includes a mix of authorities. Furthermore, a link from a DA 20 site that is highly relevant to your niche is often more valuable than a link from a DA 80 site that has nothing to do with you.
Real-World Examples / Case Studies
Case Study 1: Relevance vs. Authority
A local plumbing website with a DA of 12 ranks #1 for “Emergency Plumber [City Name].” A national home improvement blog with a DA of 65 has an article on the same topic but ranks on page 3.
Why? Google recognizes the “Local Intent” and “Relevance” of the plumber’s site for that specific query, regardless of the national site’s higher overall DA.
Case Study 2: The Growth Curve
A new SaaS company launched with a DA of 1. By publishing original research that was picked up by TechCrunch and Forbes, their DA jumped to 35 within six months. As they reached the “middle ground,” their growth slowed. It took them another two years of consistent content production to reach a DA of 55.
Best Practices for Using DA in SEO Strategy
To use Domain Authority effectively:
Benchmark Against Direct Competitors: Don’t compare your small business to Amazon. Compare it to the shop down the street.
Combine with Traffic Data: If a site has a high DA but zero traffic, stay away. It might be a manipulated “zombie” site.
Focus on “Link Relevancy”: Always prioritize links from sites in your own or related industries.
Use it as a Health Check: If your DA drops suddenly, investigate your link profile for lost links or increased spam.
Final Thoughts
Domain Authority is one of the most powerful metrics in an SEO’s arsenal, but it is a tool, not a goal. Your ultimate objective is not to have a high DA score; it is to have high traffic, high conversions, and high rankings.
A high DA is a by-product of doing SEO correctly. When you focus on creating incredible content, ensuring your technical foundations are solid, and building genuine relationships with other authoritative voices in your industry, your Domain Authority will naturally follow.
Use DA to guide your strategy, to size up your competition, and to vet your link prospects. But never forget that at the end of the day, you are optimizing for human users and Google’s complex algorithms—not for a single number on a third-party dashboard. Focus on real value, and the authority will come.
Frequently Asked Questions
Is DA a ranking factor?
No. Google does not use Moz’s Domain Authority score to rank websites.
How often is DA updated?
Moz typically updates its Domain Authority scores and link index every few weeks.
Can my DA decrease?
Yes. Your DA can decrease if you lose high-quality links, if your competitors grow significantly faster than you, or if Moz updates its algorithm to better filter out low-quality links.
What is the fastest way to increase DA?
The fastest sustainable way is through “Digital PR”—earning mentions and links from high-authority news outlets and industry publications by providing them with unique data or expert insights.
