Domain Authority Growth Calculator
Project domain authority growth over time. Enter current DA, new linking domains, quality score, and velocity to forecast DA with diminishing returns.
Page Authority Estimator
Estimate page authority on a logarithmic 0–100 scale. Enter backlink count, domain diversity, link quality, and relevance to calculate PA score.
Estimated PA⧉
37/100
Moderate
Domain Diversity⧉
0.69
Referring domains vs backlinks ratio
Link Ratio⧉
0.18
Unique domains per backlink
Quality × Relevance⧉
7/10 × 8/10
Combined link profile score
Planning notes, formulas, and examples
About the Page Authority Estimator
Page Authority (PA) is a score from 0 to 100 that predicts how well a specific web page will rank in search results. Unlike Domain Authority which measures overall site strength, PA evaluates individual page power based on backlink profile, domain diversity of linking sites, and link quality.
This estimator uses a logarithmic formula similar to how Moz calculates PA. Enter the number of backlinks, the diversity of referring domains, a link quality score, and a relevance factor to get an estimated PA for any URL.
Understanding PA helps you identify your strongest pages, evaluate competitor page strength, and determine where to focus link-building efforts. Pages with higher PA are more likely to rank well, and building internal links from high-PA pages to newer content can accelerate rankings.
Tracking this metric consistently enables marketing teams to identify campaign performance trends and reallocate budgets to the highest-performing channels before opportunities are lost.
When This Page Helps
Page Authority helps you compare the ranking potential of individual pages. Use this estimator to assess your own pages, evaluate competitor strength, and decide which pages deserve more link-building investment. It's particularly useful for content optimization and internal linking strategy.
How to Use the Inputs
- Enter the total number of backlinks pointing to the page.
- Enter the number of unique referring domains.
- Rate the overall link quality on a 1–10 scale (quality and authority of linking sites).
- Rate the topical relevance of backlinks on a 1–10 scale.
- View the estimated Page Authority score and breakdown.
- Compare PA scores across your pages to identify strengths and weaknesses.
Formula used
PA Estimate = log₂(1 + Backlinks) × Domain Diversity Factor × Quality Weight × Relevance Weight
Domain Diversity Factor = log₂(1 + Referring Domains) / log₂(1 + Backlinks)
Scaled to 0–100 logarithmic rangeExample Calculation
Result: Estimated PA: 42
With 250 backlinks and 45 referring domains, the domain diversity factor is healthy at 0.69. Quality (7/10) and relevance (8/10) provide strong multipliers. The logarithmic calculation: log₂(251) ≈ 7.97 × 0.69 × 0.7 × 0.8 × scaling factor produces an estimated PA of 42.
Tips & Best Practices
- Focus on increasing referring domains (unique linking sites) rather than total backlink count.
- High-quality backlinks from authoritative, relevant sites boost PA far more than many low-quality links.
- Internal links from high-PA pages pass authority. Link from strong pages to pages that need a boost.
- A single backlink from a DA 80 site can be worth more than 100 links from DA 10 sites.
- Monitor PA over time to track the effectiveness of your link building campaigns.
- PA is logarithmic: moving from PA 20 to 30 is much easier than moving from 60 to 70.
Understanding the Logarithmic Scale
PA uses a logarithmic scale, meaning each point becomes exponentially harder to earn at higher levels. Going from PA 10 to 20 might require a dozen backlinks, but going from 70 to 80 could require thousands of high-quality links. This mirrors how real ranking competition works: it gets harder at the top.
Link Quality vs. Quantity
A common mistake is chasing backlink count instead of quality. Ten backlinks from authoritative, topically relevant sites will boost PA far more than 1,000 links from spammy directories. Google's algorithm heavily weights the quality and relevance of linking domains.
Using PA for Competitive Analysis
Before targeting a keyword, check the PA of the top-ranking pages. If they all have PA 60+, you need a page with comparable authority to compete. If the top results have PA 20–35, the keyword is more accessible. PA comparison is one of the fastest ways to assess keyword competitiveness.
Sources & Methodology
Last updated:
Frequently Asked Questions
Page Authority is a metric developed by Moz that predicts how well a specific page will rank in search engine results. It's scored on a logarithmic 0–100 scale, meaning every incremental point becomes harder to earn at higher levels.
Domain Authority measures the overall strength of an entire domain, while Page Authority measures the strength of a single page. A new page on a DA 70 site might have a PA of 20 until it earns its own backlinks. Both contribute to ranking potential.
PA is relative to your competition. If the top results for your target keyword have PA 40–60, you need a similar PA to compete. Generally, PA above 50 is strong, 30–50 is moderate, and below 30 indicates the page needs more backlinks.
Yes. PA can drop if backlinks are lost, if referring domains stop linking, or if link quality decreases (e.g., a linking site gets deindexed). It can also relatively decrease as competitors build stronger link profiles.
PA updates as new backlinks are discovered and indexed. In practice, building enough quality backlinks to meaningfully move PA takes 2–6 months. Consistent link building through content marketing and outreach is the most sustainable approach.
Yes. Internal links pass authority (sometimes called "link equity" or "link juice") from one page to another within your site. Linking from a high-PA page to a lower-PA page can help boost the recipient's authority and rankings.
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