Domain Authority is a score from 0 to 100, invented by Moz, that predicts how likely a website is to rank compared with other sites. Google does not use it, and it still manages to be one of the most useful numbers in competitor analysis.
Both halves of that sentence matter. Here is what DA really measures, the four jobs it does well, and the situations where it will actively mislead you.
What the number actually is
Moz computes DA mostly from a site's backlink profile: how many unique domains link to it and how strong those linking domains are themselves. A machine-learning model then fits the result to how often sites win rankings in practice.
So DA is a prediction about competitiveness, trained on real search results. It is not a quality grade, not a Google signal, and not a fixed measurement. We compared it against Ahrefs' equivalent in our Moz vs Ahrefs breakdown.
The scale is logarithmic, and that changes everything
Moving from DA 10 to 20 takes a modest link push. Moving from 70 to 80 takes years of national-brand coverage.
This is also why comparing absolute numbers across niches misleads. DA 32 can make you the strongest plumber in town while DA 55 makes you a mid-table tech blog.
The four jobs DA does well
Used as designed, as a comparative gauge, DA earns its popularity.
| Job | How DA helps |
|---|---|
| Sizing up a SERP | Scan the authority range of page one before targeting a keyword |
| Qualifying link prospects | Filter outreach lists to domains worth the effort |
| Benchmarking rivals | Track your score against competitors quarter over quarter |
| Quick due diligence | Gauge a site you might buy, partner with or write for |
Notice what every job shares: DA compares one site with another. The number alone, floating free of context, means nothing.
Checking it free
Moz's Link Explorer shows DA free with an account, and its MozBar extension overlays it on every page you visit. For the Ahrefs equivalent, the free website authority checker returns DR for any domain.
Check your site, then your three closest search rivals. Those four numbers, compared, are worth more than any threshold from a blog post.
When to ignore DA completely
The score misleads in three common situations, and knowing them is what separates users from believers.
The third trap is the expensive one. Agencies get judged on a number their client can quote, so effort drifts toward score-lifting instead of revenue-lifting.
If a tactic would raise DA without plausibly raising traffic, it is decoration. Skip it.
So how much does it matter?
As a Google input: zero. As a comparative shorthand for "how hard is this site to compete with": genuinely useful, provided you compare within one tool and one niche.
Treat DA the way you treat a traffic estimate: directionally honest, precisely fictional, and best read as a trend.
The one-line takeaway: Domain Authority is Moz's prediction of ranking strength, not a Google factor. Use it to compare rivals, size up SERPs and filter link prospects, and never as a goal in itself.