Domain Authority (DA) represents one of the most widely referenced metrics in search engine optimization, despite not being directly used by search engines themselves. Understanding this metric, its calculation methodology, and its practical applications is essential for SEO professionals evaluating competitive landscapes and measuring long-term optimization efforts.
Definition and Origin
Domain Authority is a proprietary search engine ranking score developed by Moz that predicts how likely a website is to rank in search engine result pages (SERPs). The metric ranges from 1 to 100, with higher scores corresponding to greater ranking potential.1
Introduced by Moz in 2004 as a way to quantify the competitive strength of websites, Domain Authority has evolved into an industry-standard comparative metric. It is important to note that Google does not use Domain Authority as a ranking factor in its algorithm; rather, DA serves as a third-party predictor based on publicly available data and machine learning models.2
The fundamental concept underlying Domain Authority is correlation-based prediction: if website A consistently appears in search results more frequently than website B for a given set of queries, then website A should receive a higher Domain Authority score than website B.
Calculation Methodology
Domain Authority employs a machine learning algorithm trained on thousands of actual Google search results to predict ranking likelihood. The calculation incorporates over 40 distinct factors, which Moz periodically refines and reweights.3
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The quantity of unique domains linking to a website constitutes the most significant factor in Domain Authority calculation. A root domain represents a unique website; thus, 100 backlinks from a single domain count as one linking root domain, whereas 100 backlinks from 100 different domains count as 100 linking root domains.4
This emphasis on domain diversity rather than raw link quantity reflects Google's own approach to link evaluation, where links from varied sources carry more weight than multiple links from the same source.
Link Quality and Authority
Not all backlinks contribute equally to Domain Authority. Links from high-authority domains (such as major publications, educational institutions, and government websites) transfer more authority than links from low-authority sources. This concept mirrors Google's PageRank algorithm, where the value of a link depends partially on the authority of the linking page.5
The machine learning model evaluates both the quantity and quality of a domain's inbound link profile, weighing links from authoritative sources more heavily in the overall score calculation.
MozRank and MozTrust
MozRank measures link popularity on a scale from 0 to 10, functioning similarly to Google's original PageRank metric. It evaluates both the quantity of links pointing to a page and the authority of those linking pages.6
MozTrust operates on a similar 0-10 scale but measures trustworthiness based on proximity to trusted seed sites. The underlying principle suggests that trustworthy sites link to other trustworthy sites, creating networks of credible domains. Sites closely connected to high-trust domains (such as major universities, government sites, and established publications) receive higher MozTrust scores.7
Spam Indicators
Moz's machine learning algorithm compares a domain's backlink profile against patterns associated with penalized or low-quality sites. Factors contributing to spam detection include an abnormally high ratio of exact-match anchor text, links from known link farms, sudden link velocity spikes, and associations with other low-quality domains.8
Link Profile Characteristics
The algorithm also considers internal linking structure, external linking patterns, and the overall composition of a site's link graph. Sites with well-structured internal linking and selective external linking to relevant, authoritative sources typically score better than those with disorganized or suspicious linking patterns.
The Machine Learning Model
Moz trains its Domain Authority algorithm using a neural network that analyzes correlations between link data and actual search result rankings. The model is periodically retrained on updated datasets, which can cause fluctuations in Domain Authority scores even when a site's absolute link profile remains unchanged.9
This retraining process ensures the metric stays aligned with evolving search engine behavior, but it also means Domain Authority scores exist in a state of continuous recalibration rather than as fixed measurements.
The Logarithmic Scale
Domain Authority utilizes a logarithmic scale, meaning the incremental effort required to improve the score increases exponentially at higher levels. Mathematically, this means the difference in link quality and quantity between DA 20 and DA 30 is substantially less than the difference between DA 70 and DA 80.10
Practical Implications
This logarithmic structure creates several notable effects:
Ease of Early Gains
New websites can achieve relatively rapid Domain Authority growth in their initial phases. A site might progress from DA 10 to DA 30 within months through modest link acquisition efforts. The same site would require years of sustained, high-quality link building to progress from DA 60 to DA 80.
Diminishing Returns at High Levels
For established sites with Domain Authority scores above 60, even significant link acquisition campaigns may produce minimal score increases. A site earning dozens of high-quality backlinks might see its score increase by only 1-2 points, as it competes against the strongest domains on the internet.
Competitive Context
The logarithmic scale ensures that the highest scores remain reserved for truly dominant web properties. Only a small percentage of domains achieve scores above 80, and scores above 90 are limited to the most authoritative platforms on the internet (Wikipedia, major government sites, top-tier publications).
Domain Authority vs. Domain Rating
While Domain Authority represents Moz's ranking prediction metric, Ahrefs offers a competing metric called Domain Rating (DR). Understanding the distinctions between these metrics is essential for comprehensive SEO analysis.11
Calculation Differences
Domain Authority (Moz)
Uses 40+ ranking factors in its calculation
Incorporates spam signals and trust metrics
Employs a machine learning model trained on actual search results
Updates periodically during index-wide recalculations
Scored on a 1-100 logarithmic scale
Domain Rating (Ahrefs)
Focuses primarily on backlink quantity and quality
Emphasizes the strength and quantity of dofollow backlinks
Uses a simpler calculation model based on Ahrefs' proprietary UR (URL Rating) metric
Updates more frequently as Ahrefs crawls new backlinks
While DA and DR generally correlate (sites with high DA tend to have high DR and vice versa), individual domain scores can diverge significantly. These divergences typically occur when:
A domain has extensive backlinks from sources not well-represented in one provider's index
Moz's spam detection identifies issues that Ahrefs' simpler model does not weight as heavily
One metric has been updated more recently than the other
The domain's link profile characteristics align better with one calculation methodology than the other
Practical Usage
SEO professionals often reference both metrics for comprehensive analysis. Domain Authority's machine learning approach and incorporation of trust signals may better predict rankings for some queries, while Domain Rating's focus on raw backlink strength provides insight into a domain's pure link equity.13
Evaluating Domain Authority Scores
The question "What is a good Domain Authority score?" lacks a universal answer. Domain Authority is a relative metric, and score interpretation depends entirely on competitive context.
Industry Benchmarks
While acknowledging the context-dependent nature of DA scores, general ranges provide rough guidelines:
DA 1-20: Emerging or Problematic
Newly launched websites typically begin in this range, as they lack the backlink history necessary for higher scores. However, established sites in this range indicate significant SEO deficiencies requiring immediate attention.14
DA 21-40: Average Authority
This range represents typical small business websites, personal blogs, and local service providers. These sites possess basic backlink profiles but lack the authority to compete for highly competitive keywords.
DA 41-60: Good Authority
Sites in this range have developed substantial backlink profiles from quality sources. They can compete effectively for moderately competitive keywords and typically rank well within their specific niches. Achieving this range requires sustained link building efforts over multiple years.
DA 61-80: High Authority
This range indicates major industry players, established publications, and nationally recognized brands. Sites achieving these scores have developed extensive, high-quality backlink profiles from diverse authoritative sources.
DA 81-100: Dominant Authority
The highest tier remains reserved for the most authoritative domains on the internet. Examples include Wikipedia (DA 95), major news organizations like The New York Times (DA 96), and platforms like Reddit (DA 91). Few organizations outside of major platforms, government entities, and top-tier publications achieve this level.15
Competitive Analysis
Rather than targeting absolute DA scores, SEO professionals should conduct competitive analysis:
Identify the top 10-20 ranking results for target keywords
Analyze the Domain Authority scores of these ranking pages
Determine the average DA range of competitive sites
Assess the realistic effort required to achieve competitive authority levels
If target keywords predominantly feature results from DA 70+ domains, a site with DA 30 faces substantial competitive disadvantages. Conversely, if competitors average DA 35, a DA 30 site can compete effectively with targeted optimization.
Strategies for Improving Domain Authority
Domain Authority improvement requires sustained effort focused on the fundamental factors Google uses for ranking—not optimization of the metric itself. The following evidence-based strategies contribute to both DA improvement and actual ranking gains.
Acquire High-Quality Backlinks
Backlink acquisition from authoritative, relevant domains represents the most direct path to Domain Authority improvement. Research indicates that the single strongest predictor of ranking position is the number of unique domains linking to a site.16
Quality Over Quantity
A single backlink from a highly authoritative domain (DA 80+) contributes more to score improvement than dozens of links from low-authority sources. SEO professionals should prioritize securing links from:
Industry-specific authoritative publications
Educational institutions (.edu domains)
Government resources (.gov domains)
Major news organizations
Well-established industry resources
Relevance Matters
While authority is important, relevance also contributes to link value. A link from a moderately authoritative but topically relevant source often provides more SEO benefit than a link from a high-authority but irrelevant source.17
Expand Linking Root Domain Count
Given that Domain Authority emphasizes linking root domain diversity, SEO strategies should focus on acquiring that first link from new domains rather than accumulating multiple links from existing linking domains.
Conduct digital PR campaigns to earn media coverage
Contribute expert commentary to industry publications
Develop relationships with relevant industry websites
Identify and reclaim unlinked brand mentions
Develop Link-Worthy Content
Content that naturally attracts backlinks accelerates Domain Authority growth. Research on link-earning content identifies several high-performance formats:18
Original research and proprietary data
Comprehensive, authoritative guides
Interactive tools and calculators
Visual assets (infographics, charts, diagrams)
Controversial or contrarian perspectives backed by data
Statistical compilations and industry benchmarks
Content designed for link acquisition should provide unique value not readily available elsewhere, formatted for easy reference and citation.
Remove Toxic Backlinks
While acquiring new backlinks drives Domain Authority growth, removing harmful backlinks prevents negative impacts on the score. Toxic backlinks include:
Links from known link farms or private blog networks
Links from penalized or deindexed domains
Links from irrelevant or low-quality directories
Links with over-optimized anchor text
Links from hacked or compromised sites
SEO professionals should conduct regular backlink audits using tools like Google Search Console, Ahrefs, or SEMrush, then attempt to remove toxic links through direct contact or Google's Disavow Tool when removal proves impossible.19
Optimize Internal Linking Structure
While external backlinks contribute most significantly to Domain Authority, well-structured internal linking distributes authority throughout a site and improves overall SEO performance. Best practices include:
Linking from high-authority pages to important target pages
Using descriptive, keyword-rich anchor text
Creating logical content hierarchies
Ensuring important pages receive links from multiple internal sources
Avoiding orphan pages with no internal links
Research indicates that strategic internal linking can improve organic search traffic by 40% or more for properly optimized sites.20
Exercise Patience
Domain Authority improvement requires sustained effort over extended timeframes. Several factors contribute to this reality:
Calculation Frequency
Moz does not recalculate Domain Authority in real-time. The company updates scores periodically during index-wide recalculations, meaning recent link acquisitions may not reflect in DA scores for weeks or months.
The Logarithmic Challenge
As previously discussed, the logarithmic scale means each incremental point becomes progressively harder to achieve at higher levels.
Relative Competition
Since Domain Authority is relative, a site's score can decrease even if its absolute backlink profile improves, simply because competitors improved their profiles more dramatically.
Link Equity Transfer Time
Search engines require time to discover new backlinks, evaluate their quality, and transfer link equity. The full impact of a new backlink may not manifest for several months.
Realistic expectations suggest checking Domain Authority quarterly rather than weekly or monthly to avoid frustration from normal score fluctuations.
Common Misconceptions About Domain Authority
Despite widespread usage, several persistent misconceptions about Domain Authority circulate within the SEO community.
Misconception 1: Google Uses Domain Authority
Google does not use Moz's Domain Authority metric in its ranking algorithm. Google has repeatedly stated that it does not reference third-party metrics in ranking calculations.21 Domain Authority serves as a predictor of ranking potential based on factors that correlate with Google's actual ranking factors, but it is not itself a ranking factor.
Misconception 2: Higher DA Guarantees Better Rankings
While Domain Authority correlates with ranking ability, it does not guarantee superior rankings. A site with DA 50 can outrank a site with DA 70 for specific queries if it has:
Superior content relevance and quality for those specific queries
Better page-level authority (as opposed to domain-level authority)
Superior on-page optimization
Better user experience signals
More topical authority in the specific subject area
Domain Authority measures domain-level strength, whereas Google ranks individual pages based on page-level signals, content relevance, and hundreds of other factors.
Misconception 3: DA Can Be Directly Manipulated
Some SEO practitioners believe they can "hack" Domain Authority through tactics like:
Purchasing large quantities of low-quality backlinks
Participating in link exchange schemes
Building links from private blog networks
While these tactics might temporarily inflate DA scores, they violate Google's Webmaster Guidelines and risk penalties. Additionally, Moz's spam detection algorithms increasingly identify and devalue such manipulative link patterns.22
Sustainable DA growth requires the same white-hat practices that improve actual search rankings.
Misconception 4: DA Should Be Optimized Directly
Treating Domain Authority as an optimization target rather than a diagnostic metric leads to misguided strategy. SEO efforts should focus on:
Creating valuable, authoritative content
Earning high-quality backlinks through legitimate means
Improving overall site quality and user experience
Building topical authority in relevant subject areas
Domain Authority improvement follows naturally from these efforts rather than being a direct optimization target.
Limitations of Domain Authority
While valuable for competitive analysis and progress tracking, Domain Authority has inherent limitations that SEO professionals should understand.
Domain-Level vs. Page-Level Metrics
Domain Authority measures domain-level strength but does not predict the ranking potential of individual pages. A high-DA domain may host pages with poor content that rank poorly, while a moderate-DA domain may contain exceptionally strong individual pages that rank well for specific queries.23
For page-level ranking prediction, Moz offers Page Authority (PA), which applies similar methodology to individual URLs rather than entire domains.
Lack of Real-Time Updates
Domain Authority's periodic recalculation means it provides historical rather than real-time insights into a domain's authority. Recent link acquisitions or losses may not reflect in DA scores for substantial time periods.
Index Coverage Variations
Domain Authority calculations depend on Moz's link index, which may not capture all backlinks that Google sees or may include links Google has devalued. Discrepancies between Moz's index and Google's can lead to situations where DA scores do not accurately predict actual ranking ability.
Inability to Measure Content Quality
Domain Authority focuses heavily on backlink profile strength and does not directly measure content quality, user experience, technical SEO factors, or the numerous other elements Google considers in rankings. A site with excellent DA but poor content will underperform a site with moderate DA and exceptional content.24
Vulnerability to Algorithm Updates
When Moz releases updates to its Domain Authority calculation algorithm (as it did with DA 2.0 in March 2019), scores can shift dramatically across the web. These shifts reflect calculation methodology changes rather than actual changes in site authority, creating temporary confusion and misinterpretation.25
Domain Authority in Modern SEO Strategy
Domain Authority serves its most valuable function as a comparative diagnostic tool rather than a primary optimization target. SEO professionals should incorporate DA into their strategic framework through:
Competitive Benchmarking
Analyzing the Domain Authority of top-ranking competitors provides insight into the link building effort required to achieve competitive parity. This analysis helps set realistic expectations and inform resource allocation decisions.
Link Opportunity Evaluation
When evaluating potential backlink sources (guest posting opportunities, partnership possibilities, citation sources), the referring domain's DA offers a quick heuristic for prioritizing opportunities. While not the only consideration, DA provides a useful initial filter.
Progress Monitoring
Tracking Domain Authority trends over extended timeframes (quarterly or annually) helps validate that link building strategies are producing results. Consistent upward trends indicate effective link acquisition, while stagnant or declining scores suggest strategy reassessment may be warranted.
Realistic Goal Setting
Understanding the competitive DA landscape helps SEO professionals set achievable goals and select keyword targets where they can realistically compete. Avoiding head-to-head competition with domains that possess substantially higher authority improves the efficiency of SEO investments.
Conclusion
Domain Authority represents a sophisticated attempt to quantify the complex factors that influence search engine rankings through a single, accessible metric. While imperfect and limited in scope, DA provides valuable insights for competitive analysis, opportunity evaluation, and strategy development when applied with appropriate understanding of its capabilities and constraints.
The metric's true value lies not in the absolute score it produces but in its ability to provide comparative context within competitive landscapes. SEO professionals who understand Domain Authority's calculation methodology, logarithmic structure, and inherent limitations can leverage it as one component of a comprehensive SEO analytics framework.
Ultimately, strategies that improve Domain Authority—earning high-quality backlinks from diverse authoritative sources, creating exceptional linkable content, maintaining clean backlink profiles—align precisely with the white-hat SEO practices that improve actual search rankings. By focusing on these fundamental strategies rather than score manipulation, websites build the genuine authority that drives both higher DA scores and improved organic search performance.
Page, Lawrence, et al. "The PageRank Citation Ranking: Bringing Order to the Web." Stanford InfoLab, 1999, http://ilpubs.stanford.edu:8090/422/. Accessed December 2024. ↩
Moz. "Top 500 Websites: Moz Top 500." Moz, https://moz.com/top500. Accessed December 2024. ↩
Dean, Brian. "We Analyzed 11.8 Million Google Search Results. Here's What We Learned About SEO." Backlinko, https://backlinko.com/search-engine-ranking. Accessed December 2024. ↩
King, Britney. "Domain Authority 2.0: What Changed and Why It Matters." Moz Blog, 5 March 2019, https://moz.com/blog/domain-authority-2. Accessed December 2024. ↩
