Domain Authority is the SEO metric that predicts how well your site will rank on Google. Learn how it’s calculated, what a good score looks like, and why it matters.
What Is Domain Authority and How Is It Measured?
If you’ve spent any time researching SEO, you’ve almost certainly come across the term “domain authority” — and probably wondered what it actually means, whether it matters, and how to improve it.
Here’s the short answer: domain authority is a score that predicts how likely your website is to rank on Google. The higher the score, the more competitive authority your site is considered to have.
But the longer answer is more interesting — especially if you’re building, buying, or flipping websites. Because once you understand how authority is built and transferred, a whole new category of opportunity opens up.
By the end of this post you’ll understand exactly what domain authority is, how it’s calculated, what scores are considered good, and why some websites inherit authority without building it from scratch.
Why Domain Authority Exists — and What It’s Actually Measuring
What is domain authority in SEO, and does Google use it?
Domain Authority is a 1–100 score developed by Moz that predicts a site’s ability to rank in search results based on backlink quality and quantity. It’s important to know upfront that Google does not use Domain Authority as a direct ranking factor — but data shows that sites with a DA of 50 or above are roughly 3.7 times more likely to rank in the top 10 for competitive keywords than sites with a DA of 20–30.
So it’s not that DA causes rankings — it’s that DA reflects the same underlying signals that do. Think of it as a thermometer, not a heater. It measures the temperature; it doesn’t create it.
Moz’s Domain Authority scores from 0 to 100 and is based on factors like the number of sites linking to you, the quality of those links, how long the domain has been around, and the overall size of the site. Ahrefs has its own parallel metric called Domain Rating (DR), which also scores from 0 to 100 but focuses specifically on the strength of a site’s backlink profile.
Together, these two metrics — DA and DR — give SEO practitioners the clearest available picture of a site’s competitive authority.
How Domain Authority Is Calculated
DA is a logarithmic score, which has a practical implication worth understanding: improving your DA from 20 to 30 is significantly easier than improving it from 70 to 80. Progress gets harder as you climb, because you’re being measured against a much larger and more competitive pool of websites.
The core inputs that drive your score are:
Linking root domains. The number of unique external websites that link to yours. A hundred links from ten websites is less valuable than a hundred links from a hundred different websites.
Link quality. Backlinks act as votes of credibility from other sites — and just like real votes, the source matters. A link from an authoritative domain passes far more SEO value than a link from an obscure or low-quality site.
Domain age. Older domains that have accumulated trust signals over time tend to score higher, all else being equal.
Site-wide signals. Content quality, technical SEO health, and the overall size and depth of the site all contribute to the final score.
One important caveat: DA is a relative metric, not an absolute one. Because it’s calculated on a scale relative to all other sites in Moz’s index, your score can fluctuate even if nothing about your own site has changed — simply because competitor sites have improved their backlink profiles.
What Is a Good Domain Authority Score?
There’s no universal answer, because DA is always relative to your competitive landscape. A “good” DA score is contextual — a DA of 40 might be excellent in a niche industry with limited competition, while that same score could be considered weak in highly competitive sectors like finance or healthcare. The key is understanding where you stand compared to the sites you’re competing against in search results.
A rough benchmark for orientation:
- DA 1–20: New or low-backlink sites
- DA 20–40: Developing authority, competitive in lower-traffic niches
- DA 40–60: Solid mid-range, workable across most content niches
- DA 60–80: Strong authority, competitive across most industries
- DA 80–100: Reserved for major brands and publishing giants
For most affiliate sites and content sites operating in low-to-medium competition niches, a DA in the 25–45 range is workable — especially when the content is well-targeted and the competing sites are similarly modest.
Why This Matters for Expired Domain Flipping
Here’s where domain authority becomes genuinely interesting for people buying and flipping digital assets.
When a website expires and gets abandoned, its domain authority doesn’t immediately vanish. The backlinks pointing to it from external sites remain. The crawl history remains. The domain age remains. All of that accumulated authority — built over years by the previous owner — is still baked into the domain.
That means someone who registers an expired domain is inheriting a backlink profile that someone else built. They’re starting from a DA of 25 or 35 rather than zero.
For anyone building a website intended to rank, generate affiliate commissions, or sell on a marketplace, that head start is worth real money. A website with existing authority and traffic history commands meaningfully higher prices than one built from scratch — and it gets there faster. When it comes to selling, platform choice matters too: a rebuilt site with real DA carries significantly more value on Flippa than a bare domain, which is covered in detail in this comparison of Sedo, Flippa, and Afternic.
If you want to see this principle applied in a live, documented system — buying specific expired domains, filtering for genuine authority signals, rebuilding with AI, and flipping for profit – the full method is laid out in Buried Profits AI, including exactly what to look for in an expired domain’s backlink profile before you spend a dollar.
To see how this fits into the broader expired domain strategy from acquisition through to sale, the expired domain flipping guide walks through the complete process end to end.
How to Check Your Domain Authority
You can check DA for free using Moz’s Link Explorer, which gives you your current score along with linking domain counts and spam score. The MozBar browser extension lets you check DA for any site you visit directly in your browser — useful for competitive research and for evaluating expired domain candidates before you buy.
For checking multiple domains at once, Moz’s bulk analysis tool can process multiple URLs simultaneously, which is particularly valuable when working through a list of expired domain prospects.
How to Improve Domain Authority Over Time
Building DA is a long-term project, but the levers are well understood:
Earn high-quality backlinks. This is the single biggest driver. High authority backlinks from trusted websites boost credibility, improve search engine rankings, and increase organic traffic. Guest posting, creating genuinely linkable content, original research, and digital PR are the most reliable approaches.
Remove toxic links. A spam-heavy backlink profile can suppress your score. Auditing for and disavowing low-quality links through Google Search Console is worth doing annually.
Build topical depth. Authority starts with content depth, not volume. Building topic clusters rather than isolated posts, and covering search intent completely, signals to Google that your site has genuine expertise across a subject.
Technical SEO foundations. Site speed, mobile optimization, clean crawlability, and proper internal linking all contribute to the underlying health that DA reflects.
One shortcut that sidesteps years of link-building entirely: start with a domain that already has authority. That’s the core logic behind expired domain acquisition — and it’s why the strategy has grown considerably as AI tools have made rebuilding those domains fast and low-cost.
Frequently Asked Questions
Is Domain Authority a Google ranking factor? No. DA is a third-party metric developed by Moz and is not used directly by Google’s algorithm. However, the factors that drive DA — particularly backlink quality and quantity — are genuine Google ranking signals. Sites with high DA tend to rank well because they’ve done the things Google actually measures, not because DA itself influences rankings.
What’s the difference between Domain Authority and Domain Rating? Both measure backlink profile strength on a 0–100 scale, but they come from different tools. Domain Authority is Moz’s metric; Domain Rating is Ahrefs’. They use different data sources and formulas, so scores aren’t directly comparable across tools — but both serve the same purpose of estimating a site’s ranking potential based on its link profile.
Can Domain Authority decrease? Yes. Because DA is a relative metric, your score can drop even if you haven’t lost any backlinks — simply because other sites in the index have grown faster than yours. It can also drop if you lose quality backlinks, gain toxic links, or if Moz updates its scoring algorithm.
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