What Is Domain Authority? DA vs DR and What Google Uses

Domain authority is a score from an SEO tool company that estimates how strong a website's backlink profile is, compared with other sites in that company's index. Moz calls its version Domain Authority (DA). Ahrefs has Domain Rating (DR) and Semrush has Authority Score. Google uses none of them. They're handy for comparing sites, but they aren't ranking factors.

That last point gets lost all the time. Agencies put DA in proposals, link sellers price guest posts by DR, and business owners worry when their score drops by three points. So it helps to know what these numbers actually measure, why they disagree with each other, and when they're genuinely useful.

Key takeaways

Domain Authority (Moz), Domain Rating (Ahrefs) and Authority Score (Semrush) are third-party scores built mainly from backlink data, each on its own 100-point scale.
Google's John Mueller has said repeatedly that Google doesn't use domain authority at all in crawling, indexing or ranking.
The scores are relative, so they can rise or fall when nothing on your site has changed.
Use them to compare yourself with direct competitors and vet link prospects, never as a target to buy, because paid links that pass ranking credit break Google's spam policies.

What is domain authority, exactly?

"Domain authority" is now used as a generic term, but it started as a Moz product name. Each big SEO tool has its own version, built from its own crawl of the web and its own formula.

Moz Domain Authority (DA)

Moz defines Domain Authority as a score that "predicts how likely a website is to rank on search engine results pages (SERPs) compared to competitors." It runs from 1 to 100. Moz says it's calculated by a machine learning model using data from its Link Explorer index, mainly the number of linking root domains and the quality of those links. Moz is clear that DA "is not a Google ranking factor and has no effect on the SERPs." It also notes that a new website always starts at DA 1.

Ahrefs Domain Rating (DR)

Ahrefs says Domain Rating shows the strength of a website's backlink profile compared with others in its database, on a 100-point scale. In simple terms, it looks at how many unique domains link to you, how strong those domains are, and how many other sites each of them links to. On its free website authority checker, Ahrefs says DR doesn't take into account variables such as link spam, traffic or domain age. It's purely a link metric.

Semrush Authority Score (AS)

Semrush describes Authority Score as a compound metric that grades the overall quality of a website, scored from 1 to 100. Unlike DR, it blends three things: link power (the quality and quantity of backlinks), estimated organic traffic, and spam factors that look for signs of manipulation in the link profile. So a site with plenty of links but almost no search traffic can score lower in Semrush than its link count suggests.

Metric	Vendor	Scale	Main inputs	Used by Google?
Domain Authority (DA)	Moz	1-100	Linking root domains, link quality, other ranking-correlated signals (machine learning)	No
Domain Rating (DR)	Ahrefs	0-100	Unique linking domains, their strength, how many sites they link to	No
Authority Score (AS)	Semrush	1-100	Link power, estimated organic traffic, spam factors	No

Does Google use domain authority?

No. Google has said so many times, in plain language. Search Engine Journal has collected the statements from Google's John Mueller and Gary Illyes over several years. A few stand out:

In 2019 Mueller said: "We don't use domain authority, that's a metric from an SEO company."
In 2020, asked whether links from high-DA sites help: "We don't use domain authority at all in our algorithms."
Also in 2020: "Google doesn't use Domain Authority at all when it comes to Search crawling, indexing, or ranking."
In 2022, replying to someone trying to raise a DA of 31: "you do not need DA for Google Search. Google doesn't use it at all."

There's one nuance worth being honest about. In a late 2020 interview, Mueller said Google does have "some metrics that are more on a site level," as well as page-level ones. That doesn't mean Google has a secret DA. It means some of Google's signals look at a site as a whole, which isn't the same thing as a single link-based score.

What Google does confirm is that links matter. Its guide to ranking systems says Google has "various systems that understand how pages link to each other as a way to determine what pages are about," and that PageRank is still one of its core ranking systems, though it has "evolved a lot" since launch. So DA, DR and AS are rough outside attempts to model something Google measures in its own, far more detailed, way.

Domain authority vs domain rating: why the scores differ

It's normal for one site to score DA 28, DR 41 and AS 19 on the same day. There are three reasons.

Different crawls. Each company runs its own crawler and finds a different set of links. A link Ahrefs has found may not be in Moz's index yet, or ever.
Different formulas. DR is links only. Authority Score adds estimated traffic and spam signals. DA uses a machine learning model trained to predict rankings. They're answering slightly different questions.
Different scales. A DR of 40 and a DA of 40 aren't equivalent. Each vendor squeezes its raw numbers into a 100-point range in its own way, and Moz says it's much easier to grow from 20 to 30 than from 70 to 80.

The practical rule: never compare a DA with a DR, and never compare scores from the same tool months apart without checking whether the vendor changed its model.

Why your score moves when nothing has changed

These metrics are relative. Your score depends partly on everyone else's.

Moz gives a neat example. If Facebook gained a billion new links, other sites' DA would drop relative to Facebook's, because the top of the scale gets more crowded. Moz lists several reasons a score shifts: its index picks up more or fewer linking domains than the previous crawl, you gain or lose links, the scores of other big sites change, and Moz updates its algorithm, as it did with Domain Authority 2.0 in 2019.

Ahrefs says the same about DR. It calls DR "a relative term" and notes that you can lose DR without losing any backlinks, simply because other sites gained a lot of links and pushed the scale up.

So a three-point dip usually tells you about the tool, not about your website. If your Google clicks and rankings are steady, ignore it.

How to use domain authority sensibly

These scores are useful, as long as you use them for comparison rather than as a goal.

Compare yourself with the sites you actually compete with

Moz itself says there's no universal "good" score, because a 30 might be excellent in one niche and weak in another. Pick one tool and check your site and the four or five sites that rank above you for your main searches. If you're a plumber in Bristol with DR 12 and the local firms ranking above you are all around DR 15-20, the gap is small and probably closed with local links and better pages. If you're up against national comparison sites, you'll know to aim for longer-tail, local searches first.

Vet link and PR prospects quickly

When you're deciding which local paper, trade body or industry blog to approach, a score is a fast first filter. Don't stop there, though. Ahrefs itself says you should never judge the quality of a website on site-wide authority alone. Check that the site is relevant to your business, publishes real content and gets real visitors.

Spot changes in a competitor's link building

A sudden jump in a competitor's score can be a sign they've landed press coverage or started buying links. It's a prompt to look closer, not proof of anything. Our guide to competitor SEO analysis covers what to check next, and how to check backlinks for free shows where to see the links themselves.

A quick checklist before trusting a score

Use one tool consistently and note which metric you're quoting.
Compare against direct competitors, not the whole web.
Look at the linking sites, not just the number.
Check the site has real organic traffic and relevant content.
Cross-check with your own Google data before drawing conclusions.

The risk of "buying DA"

You'll find offers to "boost your DA to 50" or guest posts priced by DR. These are a bad idea for two reasons.

First, raising a third-party number doesn't raise your Google rankings, because Google doesn't use it. Tool scores can be inflated with links Google ignores or penalises.

Second, the links themselves can break Google's rules. Google's spam policies define link spam as "creating links to or from a site primarily for the purpose of manipulating search rankings." The examples include buying or selling links that pass ranking credit, excessive link exchanges, automated link-building services, and sponsored articles or guest posts with keyword-rich anchor text. Paid placements are fine if the link is marked rel="sponsored" or rel="nofollow", but then it won't pass ranking credit, which is exactly what DA sellers are promising. If you want the background on how Google enforces this, see our piece on Google spam policy changes.

What actually matters instead

If DA isn't the target, what is? Google's own guidance is fairly consistent.

Relevance. Pages that clearly answer what people in your area are searching for. A Leeds accountant's page on self-assessment deadlines beats a generic one.
Helpful content. Google says its ranking systems are designed to prioritise helpful, reliable information created to benefit people, not to game rankings.
Real links. Links you earn because you're worth mentioning: local press, suppliers, trade associations, event sponsorships (marked as sponsored), useful guides that others cite. A backlink checker for your own site shows which pages already attract them.
A site Google can crawl and index. No amount of links helps a page that's blocked or not indexed. Our free indexability checker shows whether a page can appear in Google at all.

The domain age myth

A close cousin of the DA myth is the idea that older domains rank better. Google has denied this directly. In 2017, asked whether domain age matters for ranking, Mueller simply replied "no". Search Engine Journal's review of domain age as a ranking factor reaches the same verdict: Google has said domain age is not a ranking factor.

Older sites often do rank well, but because they've had years to earn links and build content, not because of the date on the registration.

Domain age is still worth checking for other reasons. Our free domain age checker shows when a domain was registered, when it expires and who the registrar is. It's a due-diligence tool, not a ranking tool. Use it when you're buying a domain, vetting a new supplier, or wondering why a "long-established" shop asking for bank transfer was registered last month.

Use real Google data instead

The only numbers that show how Google sees your site come from Google. Search Console tells you which searches you appear for, your average position, clicks and impressions. Make It Flow's Search Console dashboard is free on every plan: connect your site and it shows your top keywords and pages, quick wins in positions 8-20, titles that are losing clicks, and a free rank tracker that uses Google's own daily average position. You can connect Bing Webmaster Tools too.

To be clear about the limits: we don't run a backlink database, so we can't show a competitor's links or give you a DA-style score. If you'd like a third-party authority number, Moz and Ahrefs both offer free checkers. For your own site, start with the Google Search Console beginner's guide and our post on free rank tracking with Search Console.

FAQ

What is a good domain authority score?

There isn't a universal one. Moz, Ahrefs and Semrush all describe their scores as relative, so a good score is one that's close to or above the sites you compete with in search. A local trades business with DA 20 may be well placed against other local firms, while a national retailer would need far more. Compare within your niche, using one tool.

Is domain authority the same as domain rating?

No. Domain Authority is Moz's metric and Domain Rating is Ahrefs'. Both are mainly built from backlinks and use 100-point scales, but they come from different link indexes and different formulas. That's why the same site often has noticeably different scores. Don't compare one with the other; pick a tool and stick with it.

Does Google use domain authority?

No. Google's John Mueller has said several times that Google doesn't use domain authority at all for crawling, indexing or ranking, and Moz itself says DA has no effect on search results. Google does use links through its own systems, including PageRank, but not any third-party score.

Why did my domain authority drop?

Usually because of the tool, not your site. Scores are relative, so they can fall when other sites gain links, when the vendor's crawl finds fewer of your links, or when the vendor updates its formula. You may also have lost some links. If your Search Console clicks and positions are steady, a small drop isn't worth worrying about.

How can I increase domain authority?

Earn links from relevant, real websites: local press, trade associations, suppliers, partners and people who find your content useful. Publish pages that genuinely answer your customers' questions. Avoid buying links or "DA boost" packages, since Google's spam policies treat paid links that pass ranking credit as link spam, and a higher tool score doesn't raise your rankings anyway.

Does domain age affect SEO?

Not directly. Google's John Mueller has said domain age doesn't matter for ranking. Older sites often rank well because they've had time to earn links and build content. Domain age is still useful when you're vetting a website or buying a domain, which is what a domain age checker is for.

What Is Domain Authority? DA, DR and Why Google Ignores Them