SEO Domain Authority

Domain Authority (DA) is a metric developed by Moz that predicts how likely a website is to rank in search engine results. It scores websites on a scale from 1 to 100. Higher scores indicate stronger ranking potential. Understanding DA helps you evaluate your own site's strength, assess competitors, and prioritize link building targets.

Who Created Domain Authority

Moz, an SEO software company, developed Domain Authority as a way to estimate a website's overall ranking strength. It is a third-party metric — Google does not use Domain Authority itself. However, it correlates strongly with actual Google rankings because it is based on the same types of signals Google values: link quantity, link quality, and link diversity.

The DA Score Scale

Diagram: Domain Authority Scale

DA 1–10   | Brand new or very weak site. Difficult to rank.
DA 11–20  | Young site with some initial links. Ranking for 
          | low-competition keywords is possible.
DA 21–40  | Growing site with consistent content and links.
          | Competitive for many mid-difficulty keywords.
DA 41–60  | Established site with strong backlink profile.
          | Competes well in most topics.
DA 61–80  | Highly authoritative site. Industry leader level.
DA 81–100 | Wikipedia, BBC, Amazon, government websites.
          | Extremely difficult to outrank.

Reference points:
  A typical new business website: DA 1–5
  A 2-year-old active blog: DA 20–35
  A major industry publication: DA 50–70
  BBC.co.uk: DA 95+

Domain Authority vs Page Authority

Moz provides two related metrics:

• Domain Authority (DA): Measures the overall strength of the entire domain. One score for the whole website.
• Page Authority (PA): Measures the strength of a specific page. Individual pages with many backlinks can have PA much higher than the site's DA.

When building links, aim for backlinks from domains with high DA AND from specific pages with high PA — ideally both.

Similar Metrics from Other Tools

Different SEO tools have their own versions of domain authority:

• Ahrefs — Domain Rating (DR): Focuses specifically on the quality and quantity of backlinks using Ahrefs' own index. Many SEO professionals consider DR the most reliable authority metric.
• Semrush — Authority Score: Combines backlinks, organic traffic, and spam signals.
• Majestic — Trust Flow and Citation Flow: Trust Flow measures link quality; Citation Flow measures link quantity.

How Domain Authority Is Calculated

Moz calculates DA using a machine learning algorithm that evaluates dozens of factors. The primary inputs are:

• Total number of backlinks pointing to the domain.
• Number of unique referring domains (each domain counts only once).
• Quality and authority of those referring domains.
• Diversity of the link profile (links from many different types of sites).

DA uses a logarithmic scale. This means increasing from DA 10 to DA 20 is much easier than increasing from DA 70 to DA 80. As DA grows, each additional point requires exponentially more effort.

Diagram: Logarithmic DA Growth

Effort required to increase DA:

DA 1 --> DA 20:   LOW effort (a few dozen quality backlinks)
DA 20 --> DA 40:  MODERATE effort (hundreds of quality links)
DA 40 --> DA 60:  HIGH effort (thousands of diverse quality links)
DA 60 --> DA 80:  VERY HIGH effort (media coverage, viral content)
DA 80 --> DA 100: Extremely rare (Wikipedia-level authority)

How to Increase Your Domain Authority

Because DA reflects your backlink profile, the path to higher DA runs through link building:

• Earn backlinks from high-DA, relevant websites.
• Diversify your referring domains — 100 links from 100 different sites beats 100 links from 1 site.
• Remove or disavow toxic backlinks that harm your profile.
• Publish content regularly to attract natural links over time.
• Build internal links to distribute authority across your domain.

Using DA for Link Prospecting

When identifying sites to pitch for backlinks, use DA as a filter. Set a minimum threshold based on your own current DA:

Your Site's DA    Target Link Prospect DA
   1 – 20         DA 20+ (aim for sites stronger than yours)
  21 – 40         DA 30+ (focus on equal or stronger sites)
  41 – 60         DA 40+ (prioritize DA 50+ for best impact)
  61+             DA 50+ (focus on highly authoritative sources)

Links from sites weaker than yours still count, but getting links from stronger sites accelerates your DA growth most efficiently.

What DA Cannot Tell You

DA predicts general ranking ability but cannot tell you whether you will rank for a specific keyword. A DA 40 site can outrank a DA 70 site for a specific query if its content is more relevant and its on-page optimization is stronger. Use DA as one signal among many, not as the only measure of SEO success.

Key Takeaway

Domain Authority is a useful benchmark for comparing website strength and evaluating link building opportunities. Focus on building diverse, high-quality backlinks to grow your DA over time. Prioritize earning links from sites with DA higher than your own, and use DR (Ahrefs) alongside Moz DA for a more complete picture of any site's authority.