Domain Authority vs. Page Authority: What DA and PA Mean

Domain Authority and Page Authority are comparative SEO metrics developed by Moz. Domain Authority estimates the relative ranking potential of an entire domain, while Page Authority estimates the relative ranking potential of one URL. Both scores use a 0-to-100 scale and machine-learning models informed largely by link data.

DA and PA are not Google metrics, and Google does not use a website’s Moz score as a direct ranking factor. Their value is comparative: they can help evaluate competitors, prospect for relevant outreach, and monitor broad changes when they are interpreted alongside search performance, content quality, technical health, and business outcomes.

What is Domain Authority?

Domain Authority, commonly abbreviated as DA, predicts how likely a domain is to rank relative to other domains in search results. Moz calculates the score with a machine-learning model that uses information from its link index. A higher number represents stronger predicted ranking potential within Moz’s model, not a guaranteed Google position.

DA should be used to compare websites in the same market or competitive set. A local service site, a new ecommerce store, and a global publisher have very different link environments, so a universal definition of a “good” score is not useful.

How is Domain Authority calculated?

The exact formula is proprietary and can evolve. Moz evaluates link-related signals from its own index and uses a model designed to correlate with rankings across search-result sets. Because the web index, model, and comparison set can change, the same site may receive a different score even when no obvious site change occurred.

What is a good Domain Authority score?

A good DA score is one that compares favorably with genuine search competitors for the topics and market you serve. Compare like with like: the sites ranking for the same queries, in the same country, and with a similar business model. Do not use a fixed threshold as a quality certificate.

Where can you check Domain Authority?

Moz provides authority metrics through products such as Link Explorer, MozBar, Keyword Explorer, Moz Pro, and its API. Other SEO platforms publish different authority-style metrics, but their names, indexes, and formulas are not interchangeable.

What is Page Authority?

Page Authority, or PA, predicts the relative ranking potential of one specific page. It uses a 0-to-100 scale and a machine-learning model similar in purpose to Domain Authority, but the evaluation is made at the URL level rather than across the whole domain.

PA can help compare pages competing for the same intent, identify important URLs with weak link support, and evaluate which existing pages may be suitable internal-link sources. It does not measure whether the content is accurate, whether the page converts, or whether Google will rank it for a particular query.

How is Page Authority calculated?

Moz’s PA model uses information about a page, including links pointing to it, and applies machine learning to estimate ranking potential. Link manipulation detection, Spam Score, and other link-based information may contribute to the model. The specific weighting is not a public checklist.

What is a good Page Authority score?

Like DA, PA is most useful as a relative measure. Compare a page with URLs that rank for the same topic and intent. A score can provide context, but the search result still depends on relevance, usefulness, eligibility, page experience, and many signals outside the PA metric.

Domain Authority vs. Page Authority

The main difference is scope. DA summarizes a domain-level prediction, while PA focuses on an individual URL. A strong domain can publish a weak page, and a particular page can attract valuable links even when the wider domain is relatively small.

• Unit measured: DA evaluates a domain; PA evaluates one page.
• Best use: DA supports domain-level comparison; PA supports URL-level comparison.
• Data source: both depend on Moz’s index and proprietary models, not Google’s private ranking systems.
• Interpretation: both scores are comparative estimates rather than guarantees.
• Actionability: a weak PA may point to a page-level opportunity, while a weak DA may reflect the wider link profile and competitive environment.

Are DA and PA Google ranking factors?

No. Domain Authority and Page Authority are third-party metrics created by Moz. Google does not read a Moz score and use that number to rank a page. A correlation can exist because Moz’s model and search engines may observe some related evidence, such as links, but correlation does not make DA or PA a Google signal.

Optimize for users and search eligibility rather than for a score alone. Helpful content, crawlable links, clear titles, relevant information, technical accessibility, and a strong overall experience are more direct areas of work.

Why do Domain Authority and Page Authority change?

Authority scores are relative and depend on a changing index and model. A score may rise or fall because your link profile changed, other sites changed faster, Moz discovered or removed links, the model was retrained, or the comparison environment shifted.

• New referring domains or important links were discovered.
• Links disappeared, changed destination, or became unavailable to the index.
• Large sites gained links and shifted the relative scale.
• Moz updated its link index, Spam Score signals, or machine-learning model.
• Redirects, canonical changes, migrations, or duplicate URLs altered how links are consolidated.

A small movement does not automatically indicate an SEO problem. Confirm the change in more than one data source and check Search Console impressions, clicks, queries, and pages before deciding that organic performance changed.

How to improve authority responsibly

You cannot directly edit a DA or PA score. Improve the real signals and assets that make the website useful and worth referencing; third-party metrics may respond later.

Create resources people have a reason to cite

Original data, expert commentary, calculators, templates, visual explanations, definitions, and practical guides can earn editorial references. The resource should add information that is difficult to replace with a generic summary.

Earn relevant links

Promote strong pages to appropriate publications, associations, partners, customers, and communities. Relevance, editorial judgment, and audience overlap matter more than the DA number displayed for the linking site.

Strengthen internal links

Connect related pages using descriptive anchors. Internal links help users navigate and distribute discovery paths across the website. Link from pages that genuinely provide context rather than inserting the same anchor into unrelated content.

Fix technical link problems

Repair broken links, redirect retired URLs to the closest valid destination, avoid unnecessary redirect chains, and make canonical signals consistent. During a migration, map old URLs carefully so valuable references are not sent to irrelevant pages.

Improve the page itself

Links cannot make a poor page useful. Align the page with search intent, update inaccurate information, improve the opening and headings, add evidence, make the mobile experience usable, and provide a clear next step.

How to use DA and PA in an SEO audit

Use the scores as supporting evidence within a repeatable audit, then connect every comparison to search data and a practical decision. A broader ranking improvement decision framework helps place authority evidence alongside content, technical, and internal-link constraints.

1. Define a relevant comparison set

Choose sites and pages that compete for the same audience and queries. Comparing a specialist business with a global news platform produces little actionable information.

2. Compare authority with search visibility

Record DA and PA, but also compare ranking queries, impressions, clicks, referring domains, link relevance, content coverage, page type, and conversion performance. Differences between these signals often reveal better opportunities than the score itself.

3. Investigate the links behind the score

Review which pages attract links, whether referring sites are relevant, and whether the references send useful traffic. A high score supported by irrelevant or manipulated links should not be treated as a trustworthy partnership signal.

4. Track trends, not daily noise

Record scores at consistent intervals and annotate migrations, campaigns, link gains, link losses, and major content changes. Evaluate meaningful trends rather than reacting to every small fluctuation.

5. Connect analysis to an action

Every observation should lead to a clear decision: improve a resource, repair a redirect, strengthen internal links, pursue a relevant mention, or leave the page unchanged. A metric without a decision is only a report. Turn the chosen decision into owners and deadlines with a prioritized 30-day SEO task plan.

DA, DR, Authority Score, and PageRank are not the same

Moz Domain Authority, Ahrefs Domain Rating, and Semrush Authority Score are produced by different companies with different indexes and formulas. They may move in different directions for the same website. Use each metric within its own platform and avoid converting one number into another.

Google PageRank is also a different concept. It originated as a way to evaluate links in Google’s systems, while toolbar PageRank scores have not been publicly updated for years. Modern Google ranking systems use many signals; a visible third-party authority score is not a replacement for them.

For reporting, name the metric and source explicitly. Instead of saying a site has “authority 45,” say it has “Moz Domain Authority 45” and record the date. That makes comparisons reproducible and prevents stakeholders from confusing a vendor estimate with a Google measurement.

Common mistakes when using authority scores

• Calling DA or PA a Google ranking factor.
• Comparing unrelated industries, markets, or page types.
• Buying links only because the selling site displays a high authority score.
• Assuming a higher score guarantees more traffic, leads, or revenue.
• Ignoring relevance, search intent, technical issues, and page quality.
• Combining Moz DA, Ahrefs DR, and Semrush Authority Score as if they use one formula.
• Reacting to a small fluctuation without checking the underlying links and search data.

Final takeaway

Domain Authority and Page Authority are useful comparative metrics when their limitations are understood. Use DA for domain-level context and PA for page-level context, but validate every conclusion with the underlying links, actual search performance, content relevance, and business outcomes. Improve the website, not merely the score.