Domain authority: definition, relevance for SEO, calculation and measurement

Why is domain authority important for SEO?

Domain authority is not a metric or ranking factor used by Google. It has no direct influence on the SERPs. But even if it is not used by Google as a ranking factor, domain authority is still important for SEO.

The respective value correlates with your ranking on the SERPs. The authority is therefore a very useful tool for mapping the SEO success or SEO performance of a website and tracking it in the long term. The higher the authority, the better.

How is domain authority calculated?

Domain authority is calculated by combining several factors, including linking root domains and the total number of links, into a single score. Since the Domain Authority 2.0 update (early 2019), the calculation of the score is based on the predictions of a machine learning algorithm.

It essentially determines how often Google uses a domain in its search results. If domain A is more likely to appear in a Google SERP than domain B, then the domain authority of domain A is expected to be higher than that of domain B.

But what is a good domain authority and how high should it be? The following scale provides some clues:

• Less than 30 is bad.
• 30 to 40 is below average.
• 40 to 50 is average.
• 50 to 60 is good.
• 60 to 70 is very good.
• Over 80 is excellent.

How can you check domain authority?

There are now many SEO tools that give you an overview of your domain authority with just a few clicks. The easiest and often most useful way is to use the (free) Link Explorer from Moz. All you have to do is enter the URL you want to check, click the start button and you will receive the desired information (+ various other link data).