What is Domain Authority (DA) in SEO?
7 min read
Domain Authority (DA) is a proprietary search engine ranking score developed by SEO software provider Moz that predicts how likely a website is to rank on search engine results pages (SERPs) compared to its competitors. Measured on a logarithmic scale from 1 to 100, Domain Authority is calculated by analyzing link data from the Moz web index, combining factors such as total linking root domains, link trust, and spam scores. While DA is widely used by marketing teams to benchmark website authority, it is a third-party metric that is not used by Google in its search algorithms.
How Domain Authority is Calculated: The Logarithmic Model
Understanding Domain Authority requires recognizing that it is a relative comparative metric rather than an absolute mathematical measurement:
- The Logarithmic Scale: Because DA is logarithmic, scaling your score from DA 20 to DA 30 requires relatively few quality backlinks. However, scaling from DA 70 to DA 80 requires exponentially more high-authority referring domains, mirroring the difficulty of competing against Wikipedia or major media outlets.
- Comparative Machine Learning: Moz calculates DA using a machine learning model trained against thousands of real-world Google search results. As millions of websites earn or lose links across Moz index, your DA score can fluctuate without any changes occurring on your site.
- Core Mathematical Inputs: The algorithm evaluates linking root domains (unique domains linking to your site), total link counts, and Moz proprietary link metrics (MozRank and MozTrust).
Domain Authority (Moz) vs. Domain Rating (Ahrefs) vs. Google PageRank
SEO practitioners frequently use third-party authority metrics interchangeably, but each platform calculates link equity differently:
| Attribute | Moz Domain Authority (DA) | Ahrefs Domain Rating (DR) | Google PageRank |
|---|---|---|---|
| Developing Entity | Moz | Ahrefs | Google (Larry Page & Sergey Brin) |
| Metric Scope | Predicts overall domain ranking potential across SERPs. | Measures relative backlink strength based purely on unique linking domains. | Calculates authoritative link equity at the individual URL page level. |
| Algorithmic Influence | Zero direct impact on Google search algorithms. | Zero direct impact on Google search algorithms. | Core Ranking Factor: Fundamental algorithmic signal inside Google ranking systems. |
| Public Accessibility | Publicly viewable via Moz Link Explorer and Chrome extensions. | Publicly viewable via Ahrefs Site Explorer. | Private; Google shut down the public Toolbar PageRank score in 2016. |
How to Build Domain Authority Ethically for B2B SaaS
Rather than obsessing over daily fluctuations in third-party scores, focus on strategies that simultaneously improve real Google rankings and third-party metrics:
- Prioritize Unique Linking Root Domains: Receiving 10 links from 10 distinct, reputable software websites passes substantially more authority than receiving 50 links from a single domain.
- Produce Primary Research and Benchmark Reports: Original data assets attract organic editorial backlinks from enterprise blogs, media outlets, and trade journals without cold email outreach.
- Eliminate Internal Broken Backlinks: Run regular crawl audits to identify legacy URLs that possess external backlinks but return 404 errors. Restore link equity by setting up 301 redirects to relevant active pages.
Frequently Asked Questions
What is considered a good Domain Authority for a B2B SaaS company?
A "good" DA is relative to your direct competitors. An early-stage startup might succeed with a DA of 25 to 35 in a narrow niche, whereas enterprise cloud categories require a DA of 60 to 75+ to compete for broad commercial search queries.
Why did my Domain Authority drop when my traffic increased?
Because DA is a comparative metric calculated across Moz entire web index. If other major websites add millions of quality links faster than your site, your relative score can decrease even as your organic traffic and Google rankings improve.
Does Google have an internal domain-level authority metric?
Google has stated that it does not use a single "domain authority" score. However, Google maintains entity-level trust signals, sitewide quality modifiers, and uses PageRank to calculate authority across web graphs.