Definition
Domain Authority (DA) is a search engine ranking score developed by Moz that predicts how likely a website is to rank in search engine results pages (SERPs). Scored on a logarithmic scale from 1 to 100, DA is calculated based on the number and quality of backlinks pointing to a domain. It is a comparative metric — useful for benchmarking against competitors rather than as an absolute measure of quality.
Why It Matters
Domain Authority has become one of the most widely used metrics in SEO for evaluating the competitive strength of a website. While it is not a Google ranking factor, it serves as a valuable benchmark.
- Competitive analysis. DA allows you to compare your domain's link profile strength against competitors. If your competitors have DA scores of 50-60 and yours is 25, you know you need a significantly stronger backlink strategy to compete for the same keywords.
- Link building prioritization. When evaluating potential backlink opportunities, DA helps you assess the value of a linking domain. A backlink from a DA 70 site carries more weight than one from a DA 15 site.
- Progress tracking. While DA should not be your primary KPI, tracking it over time shows whether your off-page SEO efforts are strengthening your domain's authority.
- Indirect AI relevance. AI models do not use DA scores, but they do consider the authority signals that DA measures. Websites frequently referenced by high-authority sources are more likely to be cited in AI-generated answers. Brands mentioned on authoritative third-party platforms are cited 6.5x more often by AI assistants.
Understanding DA is part of a broader SEO strategy that includes both on-page and off-page optimization.
How It Works
Domain Authority is calculated using a machine learning model that evaluates multiple factors related to a domain's backlink profile. Here is how it works under the hood:
Key calculation factors
- Linking root domains. The number of unique domains that link to your website. A link from 100 different domains is far more valuable than 100 links from a single domain.
- Total backlink count. The total number of individual links pointing to your site, though quality matters more than quantity.
- Link quality. Links from high-authority, relevant domains contribute more than links from low-quality or unrelated sites.
- Domain age and history. Older domains with consistent link growth tend to have higher DA.
- Spam score. Moz penalizes domains with link profiles that appear manipulative or spammy.
The logarithmic scale
DA uses a logarithmic scale, which means it is much easier to improve from 20 to 30 than from 70 to 80. Each incremental point requires exponentially more link equity. A site with DA 50 is not "twice as strong" as DA 25 — it is many times stronger.
DA vs. similar metrics
Several SEO tools offer their own authority metrics:
- Domain Authority (DA) — Moz's metric, based on their proprietary link index
- Domain Rating (DR) — Ahrefs' equivalent, using their own backlink database
- Authority Score (AS) — Semrush's version, incorporating traffic and spam signals alongside links
- Trust Flow / Citation Flow — Majestic's dual metrics measuring link quality and quantity separately
These metrics often produce different scores for the same domain because they use different data sources and algorithms. None of them is "better" — choose one and use it consistently.
Common misconceptions
- DA is not a Google metric. Google has repeatedly stated it does not use Moz's DA or any third-party authority score in its ranking algorithm.
- A high DA does not guarantee rankings. DA measures domain-level signals, but Google ranks individual pages using hundreds of additional factors.
- DA can be manipulated. Purchasing spammy backlinks can artificially inflate DA temporarily, but this damages long-term SEO health.
- DA fluctuates. Your DA can change even if you do nothing — because Moz regularly updates its index and algorithm, and your competitors' link profiles change constantly.
For strategies on building genuine domain authority through quality backlinks, see our off-page SEO guide.
Frequently Asked Questions
Is Domain Authority a Google ranking factor?
No. Domain Authority is a metric created by Moz, not by Google. Google does not use DA in its ranking algorithm. However, DA is a useful proxy because the signals it measures — backlink quality, linking root domains, and domain trustworthiness — correlate with signals that Google does consider. Use DA as a competitive benchmark, not as a direct ranking indicator.
Does Domain Authority affect AI visibility?
Not directly. AI models like ChatGPT, Gemini, and Perplexity do not use Moz's DA score. However, the underlying authority signals — quality backlinks, mentions on trusted third-party sites, brand presence across the web — do influence AI citation. Research shows brands referenced on authoritative external platforms are cited 6.5x more often by AI than brands visible only on their own domain.
What is a good Domain Authority score?
DA is relative to your competitive landscape. For small businesses, a DA of 20-40 is typical. Established companies with active SEO programs usually fall in the 40-60 range. Scores above 60 are strong, and above 80 is reserved for major brands and media outlets. Rather than targeting a specific number, compare your DA to your direct competitors and work to close any gaps.
Authority alone does not guarantee AI visibility
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