Domain authority (aka website authority) is a search engine metric used to estimate how well a website will rank on search engine results pages (SERPs) as a whole. This metric is crucial for your SEO strategy.
That’s the simple definition.
Here’s where it gets a bit tricky.
If you hear someone talking about domain authority, they could be talking about one of two ideas.
The first is the Google ranking factor.
This is the idea that, in search results, Google favours some sites more than others based on how authoritative the site is.
This is also called “site authority”.
The second idea is the Moz metric.
SEO research company Moz created a metric to predict how high a page will rank. It uses a series of important factors, including the quality of domains pointing to the website, the number of inbound links, and other proprietary factors.
The domain authority (DA) score rates a website on a scale of one to 100, with 100 being the best-rated website.
A high DA influences how well your website can rank highly (and even outrank competitors) on search engines.
When you hear someone say, “that website has a domain authority of 58,” they’re referencing Moz’s score.
Here’s the catch:
According to Google, the first type of domain authority does NOT exist.
That’s why, in this article, we’ll talk about the metric developed by Moz.
Just keep in mind that people still refer to the Google ranking factor.
Why measure Domain Authority?
The great thing about domain authority is that it gives you a benchmark for your website.
You can see how your site compares to other websites, as well as tracking the ranking strength of your website over time.
How is Domain Authority calculated?
The domain authority of a website takes heaps of different factors into its calculation.
To really understand how domain authority is calculated, we need to know how Google ranks websites in the SERPs.
Before Google returns search results, it considers more than 200 factors.
Nobody but Google understands precisely what all those factors are, nor their weighting, but experience gives us a pretty good idea of what makes the highest-scoring pages show up first.
You might remember when Google’s PageRank was the most popular public tool for measuring the quality and authority of a specific page.
For any page, you could see the Google PageRank score on a logarithmic scale from 0–10, which considered:
Quantity and quality of inbound linking pages
Number of outbound links on each linking page
PageRank of each linking page
Then, in 2016, Google took it away after it died a slow and painful death.
Now Moz’s Domain Authority fills that gap. Well, almost.
Just like Google, Moz uses its own collection of metrics (over 40 of them) to calculate a site’s DA.
These include the number and quality of links into your site, domain age, popularity, size, trust scores and other Moz-proprietary factors.
It's a complex algorithm, but thankfully not as complex as Google's.
But it’s about to get more complicated.
Just like the old PageRank, Moz also scores Domain Authority on a “100-point logarithmic scale”.
This means it's easier to grow your score from 10 to 20 than it is to grow from 80 to 90.
What is a good Domain Authority score?
Here’s the thing about domain authority: it’s designed to be a comparative metric.
So, there isn’t a definitive "good" or "bad" Domain Authority score. It’s all relative.
That said, there are a few general rules:
“Good” scores often have lots of high-quality external links (e.g. Wikipedia or Google).
Small businesses and websites with fewer inbound links tend to have lower DA score
Brand-new sites always start with the lowest Domain Authority score of one
Okay, we know you still want to know what a “good” score is.
As a guide, the average domain authority is between 40 and 50.
Over 60 is considered excellent.
Though again, this measure of success differs wildly from industry to industry.
If all your competitors are averaging a Domain Authority of 20 to 30, then reaching 40 will see you outrank them fairly quickly.
Are there any sites with a perfect 100?
How is domain authority different from page authority?
You can have a higher page authority than domain authority, and vice versa.
Both are important to your search visibility.
But we’re going to say that generally, you should prioritise Domain Authority, as it will have an impact across all your web pages and is a better long-term investment.
That said, if you want to compete for a specific high-value keyword, you may want to target a single page authority for a while.
How do you find out a website's Domain Authority?
Here’s the good news:
You don’t have to sit for hours juggling numbers and calculating various website elements.
Domain authority is a public number – you can find it quickly and for free.
Simply go to Open Site Explorer and enter the URL.
Here’s what you’ll see:
Image credit: Crazy Egg
If you’ve signed up for free access to Moz, you can see basic metrics.
You’ve got to invest in the paid version for even deeper insights into how scores were calculated.
How to improve your domain authority
On page SEO involves optimising what’s already on your website. This is just one part of your overall SEO efforts.
Earning quality links back to your website is the other essential component.
It’s no secret that Google looks to inbound links to rank the authority and trustworthiness of a domain.
But not just any old links.
You need to focus on link building – high quality links that tell Google that your website is worth sharing, linking to, and talking about.
Your online presence according to your inbound links and outbound links is called your link profile.
Once you have these links, make sure you regularly evaluate them.
Get rid of any bad ‘spammy’ backlinks too. They’re not doing you any favours.
Now you know all you’ve ever wanted to know about domain authority.
Here’s a quick summary:
What is domain authority? Domain authority is a good, quick way to predict if a website is likely to rank well.
What’s a good domain authority? It’s all relative!
Is domain authority useful? Yes. It’s a great tool to compare your site with the competition and track improvements over time.