Domain Authority (DA)

What is Domain Authority (DA)?

Domain Authority is a score from 0 to 100 created by Moz that predicts how likely a website is to rank in search results. Like Domain Rating, it is calculated largely from the link graph, and like DR it is logarithmic, so the higher you climb the harder each point becomes.

The difference in intent is worth knowing. DR is a fairly direct measure of backlink strength. DA is a machine learning model that Moz trains to predict ranking ability, and it gets retrained periodically. That means your DA can move without you doing anything, simply because Moz changed how the model works or recrawled the web.

As with DR, Google does not use Domain Authority. There is no internal Google score called domain authority. Google representatives have said this repeatedly, and it remains one of the most persistent misunderstandings in SEO, partly because the phrase sounds like something a search engine would obviously have.

DA and DR side by side

	Domain Authority	Domain Rating
Made by	Moz	Ahrefs
Scale	0 to 100, logarithmic	0 to 100, logarithmic
Measures	Predicted ranking ability	Backlink profile strength
Underlying index	Moz crawl	Ahrefs crawl
Used by Google	No	No

Because they run on different crawls, the same site frequently scores differently on each. A domain at DA 40 might be DR 32, or DR 48. Neither is wrong. They are two companies estimating the same underlying thing with different data and different methods.

Why Domain Authority matters for startups

Mostly it matters because other people will quote it at you. Directory owners, guest post sellers, and agencies routinely cite DA in their pitches, so understanding what it does and does not mean protects you from paying for the wrong thing.

It is also a reasonable second opinion. If a site shows healthy on one metric and poor on the other, that gap is worth a look. Sometimes it means one crawler has simply seen more of the web. Sometimes it means the profile is inflated with links that one index counts and the other discounts.

Domain Authority in practice

You get an email offering a guest post on a site with "DA 55, great for SEO". Before paying, you check the same domain and find DR 12. That is a large enough gap to investigate.

Looking closer, the site has a small number of very old links from a few strong domains, which the Moz model rewards, and almost no recent editorial coverage. Its published posts have no organic traffic. The DA number is technically accurate and commercially meaningless. You decline, and put the budget toward a niche startup directory at DR 30 that actually sends visitors.

Rules of thumb

Pick one metric and stay with it, because switching between DA and DR makes your own tracking incoherent. Most founders default to DR simply because the Ahrefs index is larger, and because a free check is easy to run.

Whichever you choose, treat both as relative rather than absolute. The useful question is never "is DA 40 good", it is "how does this compare to the sites I am competing with, and to where I was three months ago".

Common mistakes

• Believing Google uses it. It does not, and no amount of confident marketing copy changes that.
• Paying a premium for a high DA link. The price often reflects the metric rather than the traffic or relevance, which is the wrong thing to buy.
• Comparing DA to DR directly. Different scales from different indexes. A DA 40 site is not "better" than a DR 35 site; the two numbers are not comparable.
• Panicking at a drop. Moz retrains the model periodically, and scores shift across the whole web when it does. A drop is often a recalibration, not a penalty.

Related concepts

Both scores are downstream of the same thing: who links to you, and how much those linking sites are themselves trusted. That makes referring domains and backlinks the metrics worth working on directly, since they are what you can actually influence. To see where a specific page stands rather than the whole domain, look at URL Rating, and to compare your site against a competitor across on-page factors as well as authority, run the website comparison tool.