Domain Authority Explained: What DA Actually Measures (and What Google Ignores)
Moz DA, Ahrefs DR, and Majestic TF are comparative link scores—not Google ranking factors. Here is how to use them for comps and expired-domain due diligence without chasing the wrong number.
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"What's the DA?" is the first question in expired-domain forums—and often the wrong one.
Domain Authority (DA) is a Moz-proprietary score (1–100) predicting relative ranking potential from link data (Moz definition). It is not a Google metric. Google does not read Moz, Ahrefs, or Majestic dashboards when ranking pages—John Mueller has stated publicly that third-party authority scores are not used in Google's algorithm.
DA is a compass for comparing link profiles, not a dial you turn to rank.
The metric map: same idea, different vendors
| Metric | Vendor | Scale | Primary inputs | | --- | --- | --- | --- | | Domain Authority (DA) | Moz | 1–100 (logarithmic) | Linking root domains, MozRank/MozTrust, ML model vs SERP data | | Domain Rating (DR) | Ahrefs | 0–100 | Referring domains + their DR (recursive) | | Trust Flow (TF) | Majestic | 0–100 | Link trust classification | | Citation Flow (CF) | Majestic | 0–100 | Link volume (not trust) | | Brand Authority (BA) | Moz | 1–100 | Brand search/popularity signals (US/UK/CA/AU) |
Receipt on logarithmic scale: Moving DA 20 → 30 is far easier than 70 → 80—Moz explicitly models diminishing returns.
2025+ nuance: Moz added Brand Authority alongside DA because link-only scores miss brand-query strength (Moz Brand Authority). A site can rank with moderate DA if the brand is searched often.
What Google actually uses (vs what tools proxy)
Google's public guidance emphasizes:
- Relevant, quality content matching intent
- Helpful, people-first pages (E-E-A-T signals)
- Links as citations—but evaluated algorithmically, not via Moz's score
- Technical crawlability, Core Web Vitals, spam policies
Correlation ≠ causation: High-DA sites often rank because they earned real links and brand demand—not because DA appears in Search Console.
How to use DA/DR responsibly
1. Competitive benchmarking
Compare your DA/DR to direct SERP competitors, not random "DA 80" blogs in unrelated niches.
Example: Local HVAC site at DA 28 competing against directories at DA 45—gap explains outreach difficulty; target DA 30–40 local publishers, not Forbes.
2. Link prospecting filter
Guest post targets: sites with DR/DA modestly above yours and real traffic in your topic. A DA 60 site with pharma spam outbound links is worse than DA 35 niche editorial.
Check: Ahrefs/Moz spam flags, outbound link quality, indexing status.
3. Expired / aftermarket domain due diligence
Investors sometimes buy aged domains for link equity. DA alone is insufficient.
| Check | Why |
| --- | --- |
| Wayback history | Adult/pharma/spam eras poison value |
| Referring domain relevance | 500 links from .xyz blogs ≠ 5 links from industry press |
| Anchor text profile | Over-optimized money anchors trigger penalties |
| TF/CF ratio (Majestic) | CF ≫ TF suggests low-trust volume |
| Google indexing | site:domain.com should show clean pages or none—not spam |
| Trademark / UDRP | Prior disputes = liability |
Receipt: A domain can show DA 40 with toxic links—post-acquisition rankings may drop, not jump.
See How Domain Names Affect SEO for EMD vs brandable nuance.
Myths that cost money
| Myth | Reality | | --- | --- | | "Buy links to raise DA" | Spam links risk manual actions; DA may rise briefly then collapse | | "DA 50 guarantees page 1" | Page-level signals, intent match, and competition matter more | | "Higher DA domain = always worth premium" | Verify link quality before aftermarket bids | | "All authority scores agree" | Same site: DA 42, DR 58, TF 22—normal divergence | | "DA updates instantly" | Moz/Ahrefs refresh on crawl cycles—weeks of lag |
Improving the signals DA approximates (the right goal)
- Earn editorial links—original research, tools, data studies
- Fix toxic links—disavow only when necessary (Google treats disavow as hint)
- Build brand search—BA rises when people query your name
- Internal linking—distributes equity to money pages (doesn't change DA much, changes rankings)
- Digital PR—HARO alternatives, journalist outreach in your vertical
Chasing DA as a KPI is backwards. Chase referring domains you'd be proud to show a customer.
Domain selection angle
For new registrations, DA is zero by definition—ignore it.
For aftermarket buys, use DA/DR as a screen, then run the due diligence table above. Price from NameBio comps, not from Moz's "domain value" guesses.
China context
- Baidu does not use Moz DA; it uses its own link and trust signals (备案, site age, content compliance)
- When buying
.cnaged domains, add ICP history and 内容合规 review—not just Ahrefs DR - Domestic SEO tools (5118, Aizhan) provide Chinese backlink views Moz misses
Errors fixed from beginner DA posts
| Old claim | Fix | | --- | --- | | "DA is how Google scores you" | Third-party estimate only | | "Raise DA = raise rankings" | Improve links + brand + content; DA may follow | | "One metric is enough" | Use DR + TF/CF + traffic + history | | Ignored Brand Authority | Brand queries matter in 2026 SERPs + AI Overviews |
Bottom line
Domain Authority answers: "How strong is this site's link profile vs others in Moz's model?"
It does not answer: "Will Google rank this page tomorrow?"
Use DA/DR to compare, prospect, and price—then verify with history, relevance, and traffic. Let the score be a compass, not the destination.
Next: Choosing a Domain Name · Website Speed & SEO · Expired Domains
