Domain Authority

What Is Domain Authority?

Domain Authority was developed by the SEO software company Moz as a way to estimate, in a single comparable number, how "strong" a website is likely to be in search rankings relative to other sites. It's calculated using a machine-learning model trained on search engine ranking data, factoring in elements like the total number of linking root domains and the total count of backlinks pointing to a site. A critical thing to understand: Domain Authority is not an official Google ranking factor. Google has never confirmed using DA, or any equivalent proprietary third-party score, as part of its actual ranking algorithm. Instead, DA is best understood as an independent, predictive estimate — useful for comparing sites relative to one another, but not a metric that search engines themselves consult. DA scores are logarithmic, not linear: moving from a DA of 20 to 30 is meaningfully easier than moving from 70 to 80, because at the higher end a site is already competing with some of the most authoritative domains on the web. Several similar competing metrics exist from other SEO tool providers, each with its own proprietary formula and scale, meaning a site's score can and often does differ between tools.

Why Domain Authority Matters for SEO

A Simple Example

Two blogs both publish similar-quality articles about sustainable gardening. Blog A has been online for eight years, earned links from several established gardening and lifestyle publications, and has a DA around 45. Blog B launched six months ago with a handful of low-quality directory links and a DA around 8. All else equal, Blog A's pages are statistically more likely to rank well, not because DA itself is a ranking factor, but because the underlying signals it's modeling — link quantity, quality, and diversity — are genuinely correlated with ranking performance.

Best Practices

• Focus on the underlying signals, not the score itself — earn high-quality, relevant links and the score will follow.
• Prioritize link diversity — a wide range of unique linking domains tends to matter more than raw link volume.
• Be patient — DA typically builds gradually, and sudden spikes can indicate manipulative link acquisition.
• Use DA as one input among many, combined with relevance, traffic estimates, and content quality.
• Don't obsess over exact numbers, since DA differs across tools and updates periodically.

Common Mistakes to Avoid

• Treating DA as a Google ranking factor and optimizing purely to move the number.
• Comparing DA scores across different tools, which use different formulas and aren't interchangeable.
• Chasing quick DA boosts through low-quality links, risking search engine penalties.
• Ignoring page-level authority — a high domain-wide score doesn't guarantee every individual page ranks well.