Domain Authority

Domain Authority (DA) is a proprietary SEO metric developed by Moz. It predicts how likely a domain is to rank in search results relative to other domains, using a score from 1 to 100. As a third-party comparison metric, Domain Authority is not a Google ranking factor. DA essentially provides a comparative estimate of a domain’s ranking potential.

Moz calculates DA through a machine-learning model based primarily on link data. Because the metric is recalculated over time, a website’s score can change even when no obvious change has occurred on the website itself.

The DA score is relative rather than absolute, which makes it more useful for comparing domains with similar competitors. One can check any domain using the Moz Free Domain Authority Checker or by installing the free MozBar browser extension to view authority metrics for search results. Free access, however, may be subject to account or usage limits.

Calculation Methodology

Moz calculates Domain Authority using a machine-learning model that analyzes backlink signals from Moz’s Link Explorer index. The resulting score is presented on a logarithmic scale from 1 to 100, with higher scores indicating greater predicted ranking potential relative to other domains.

• Logarithmic Scale: Increasing a DA score becomes progressively more difficult at higher levels. For example, moving from 10 to 20 is generally easier than moving from 70 to 80, but no fixed number of backlinks guarantees a particular increase.
• Machine-Learning Inputs: Moz combines multiple link-related signals, including the number of linking root domains and total links, into a single predictive score. The exact weighting is proprietary and may change when Moz updates its index or retrains the model.

Because DA is relative, a score may change when Moz updates its link index or recalibrates its model. DA should therefore be used to compare similar competitors rather than treated as an absolute grade of website quality.

What Is a Good Domain Authority Score?

Because DA is a relative metric, there is no single “good” score. A useful benchmark is a score comparable to or higher than those of direct competitors operating in the same niche, market, and stage of development.

Platforms with the Highest DA Scores

At the time of writing, the highest tiers in Moz’s current Top 500 list are dominated by internet infrastructure giants and top social networks, including Google (100), YouTube (100), Blogger (100), LinkedIn (99), and WhatsApp (99).

Domain Authority vs. Page Authority

Domain Authority and Page Authority are both predictive SEO metrics developed by Moz. Although they use the same 1–100 scoring scale, they estimate ranking potential at different levels.

• Domain Authority (DA): Predicts how likely an entire domain or subdomain is to rank in search results.
• Page Authority (PA): Predicts how likely a specific webpage or URL is to rank in search results. A homepage often has a higher PA score than a newly published article because it typically has accumulated more internal and external links, although this is not always the case.

Competitor Metrics: Ahrefs and Semrush

Other major SEO platforms like Ahrefs and Semrush also provide their own comparable proprietary scores using slightly different calculation models:

• Domain Rating (DR) by Ahrefs: Ahrefs’ Domain Rating measures the strength of a website’s backlink profile on a logarithmic scale from 0 to 100. Its calculation considers referring domains, the DR of those domains, and how many other websites they link to.
• Authority Score (AS) by Semrush: Semrush’s Authority Score is a compound metric scored from 1 to 100 based on link power, estimated organic traffic, and spam-related Natural Profile signals. 

DA, DR, and Authority Score are not directly interchangeable because each provider uses a different index and calculation method. A DA of 50 should not be treated as equivalent to a DR or Authority Score of 50.

Importance for SEO

Google does not use Moz’s DA, Ahrefs’ DR, or Semrush’s Authority Score as ranking signals. However, these metrics remain useful for competitor benchmarking and initial link-prospect evaluation because they summarize information about backlink profiles.

Domain Authority can be useful as an initial comparison metric when evaluating competitors or potential link opportunities. However, DA does not measure Google’s PageRank or reveal how much ranking value a specific backlink may provide. Google uses its own link-analysis systems, including PageRank, alongside many other ranking signals.

Websites with stronger backlink profiles often compete more effectively for difficult keywords, which is why higher DA commonly correlates with stronger search performance. However, DA does not reproduce Google’s algorithms or measure PageRank directly.

Well-linked websites may be discovered and crawled more readily because Google uses links to find new pages. A strong link ecosystem may provide some resilience during algorithm changes, although this should not be treated as protection against ranking losses. Google’s core-update guidance emphasizes broader content quality, relevance, and sustainable improvements rather than any single authority metric.

Overall, DA or other proprietary metrics should not be used as the only criterion when evaluating a backlink opportunity. Topical relevance, page quality, organic traffic, editorial placement, indexability, and the referring page’s outbound links should also be considered.

Factors That Influence the DA Score

Moz does not disclose every input or weighting used in its machine-learning model. However, Moz explains that Domain Authority is calculated through a machine-learning model that evaluates multiple link-related signals.

• Linking Root Domains: The number of unique websites linking to a domain is one of the link-related inputs considered by Moz’s model. Links from a wider range of established linking domains can strengthen the overall backlink profile.
• Spam and Link Patterns: Moz’s DA model considers Spam Score and patterns in link data intended to make the metric more resistant to manipulation. The exact weighting of these signals is proprietary.
• Moz Index and Relative Changes: A DA score may rise or fall even when no major website changes have occurred. This happens when Moz discovers new links, removes lost links, updates its link index or retrains its calculation model.

How to Increase a Website’s DA Score

Improving Domain Authority should be treated as a possible result of building a stronger backlink profile rather than as an SEO goal by itself. This is because a higher DA does not directly lead to higher Google rankings.

A DA score may improve as Moz detects a stronger and more diverse backlink profile. However, because Domain Authority is relative, no individual action guarantees a particular score increase. To improve the website’s DA score, it is important to:

• Earn Quality Backlinks: Seek genuine links from reputable and relevant publications, professional communities, partners, journalists, and other credible websites.
• Create Link-Worthy Resources: Publish original research, detailed guides, templates, calculators, and tools that provide a genuine reason for other sites to link.
• Diversify Referring Domains: Earn links from a broader range of relevant websites instead of repeatedly obtaining links from the same sources.
• Recover Valuable Backlinks: Restore or appropriately redirect relevant broken pages that have already earned external links.
• Avoid Manipulative Link Building: Do not purchase bulk backlinks, participate in link networks, or use automated schemes intended only to inflate domain authority metrics.