What is domain authority? Meaning, scale and how Moz calculates it
Updated
The short answer
Domain authority (DA) is a score from 1 to 100, created by Moz, that predicts how likely a whole website is to rank in search results compared with other sites. It's calculated mostly from the number and strength of the unique websites linking to it. The scale is logarithmic and relative, and Google doesn't use it.
Key facts
- Owner: Moz. The official name is Domain Authority, often shortened to DA.
- Scale: 1 to 100. Every brand new website starts at 1.
- Main input: linking root domains and how strong those linking sites are.
- Logarithmic: going from 20 to 30 is much easier than going from 70 to 80.
- Relative: your score can move when other sites gain or lose links.
- Not a Google ranking factor, but it tracks the link signals Google does reward.
What domain authority means in SEO
Domain authority is a forecast. Moz looks at a website's link profile and estimates how well that site should be able to rank compared with everything else in its index. A higher number means a stronger link profile and, usually, an easier time ranking for competitive keywords.
The word that matters most here is compared. DA has no meaning on its own. A score of 35 tells you nothing until you know that the five sites ranking for your target keyword sit between 28 and 42. Then it tells you a lot: you're in the same league and the fight will be won on content and relevance, not raw link power.
That's why we treat DA as a sizing tool. It answers one practical question: is this site strong enough to compete here, or will it need more links first? You can check that number for any site in seconds with our domain authority checker, which also shows Page Authority, Spam Score, Trust Flow and domain age in the same report.
How Moz calculates domain authority
Moz trains a machine learning model on thousands of real search results. The model learns which link patterns show up on sites that rank well, then scores every domain in the Moz link index by how closely it matches those patterns. The final number is rescaled onto 1 to 100.
Moz says the model uses dozens of factors, but the heaviest weight sits on links. The inputs that move DA the most are:
- Linking root domains: how many different websites link to you. Ten links from ten sites beat a hundred links from one site.
- Strength of those sites: a link from a site with a strong profile counts for far more than one from a site nobody links to.
- Link quality signals: patterns the model associates with ranking sites rather than with spam or manipulated profiles.
Content quality, page speed, traffic and on-page keywords are not part of DA. Two sites with identical link profiles get the same score even if one of them is far more useful. Keep that in mind before reading too much into the number.
Why the scale is logarithmic
The top of the scale is crowded with giants. Sites like YouTube, Wikipedia and major news outlets have millions of linking domains, and they occupy the 90s. To make room for everyone else, each step up the scale needs far more link strength than the step before it.
In practice it looks like this: a new blog can climb from 1 to 15 with a handful of decent links. Getting from 15 to 30 might take a year of steady work. Getting from 60 to 70 can take a serious brand with real press coverage several years. Plan your goals with that curve in mind.
| DA range | Typical sites | Effort to climb |
|---|---|---|
| 1 to 20 | New sites, personal blogs, small local businesses | Low: a few genuine links move it |
| 21 to 40 | Growing niche sites and established small businesses | Moderate: consistent link earning for months |
| 41 to 60 | Respected niche publishers, popular SaaS and ecommerce brands | High: needs a real content or PR engine |
| 61 to 80 | National brands, large publications, big platforms | Very high: years of coverage and citations |
| 81 to 100 | The most linked sites on the web | Out of reach for almost everyone else |
Want to know where a specific number lands for your niche? Our guide on what counts as a good domain authority breaks the ranges down by site type and competition level.
Why domain authority changes
DA is relative, so it can move even when nothing on your site changes. Moz gives a neat example: if one huge site suddenly gained a billion new links, every other site would slide down a little, because the top of the scale just got harder to reach.
The common causes of a change are new links being discovered, old links disappearing, Moz recalculating its model, and competitors growing faster than you. A drop of one or two points is normal noise. A drop of ten deserves a look at which links went missing, and we cover that step by step in why domain authority drops.
Domain authority vs page authority
Domain authority scores a whole website. Page Authority (PA) uses the same kind of model but scores one URL, based on the links pointing at that specific page. A site can have a DA of 50 while a brand new article on it sits at PA 10.
Use DA to compare websites and PA to compare the actual pages you're up against in a search result. Our page authority guide explains when each one is the better signal.
DA compared with other authority metrics
Moz isn't the only company scoring site strength. Each tool runs its own crawler and its own formula, so the same domain gets a different number in each one. None of them is more correct than the others; they just see different slices of the web.
| Metric | Company | Scale | What it measures |
|---|---|---|---|
| Domain Authority (DA) | Moz | 1 to 100 | Predicted ability of a whole domain to rank |
| Page Authority (PA) | Moz | 1 to 100 | Predicted ability of a single page to rank |
| Domain Rating (DR) | Ahrefs | 0 to 100 | Strength of the backlink profile |
| Trust Flow (TF) | Majestic | 0 to 100 | How close a site is to trusted seed sites (link quality) |
| Citation Flow (CF) | Majestic | 0 to 100 | How much link equity flows to a site (link volume) |
| Authority Score (AS) | Semrush | 0 to 100 | Links, organic traffic and spam signals combined |
The full comparison, including why your DA and DR rarely match, is in Domain Authority vs Domain Rating vs Trust Flow.
How to use domain authority without being misled
DA is useful when you treat it as one input among several. These are the habits we'd recommend:
- Compare inside one niche. A DA 25 plumber can be the strongest site in town. A DA 25 tech publisher is small.
- Track the trend, not the day. Check monthly and look at the direction over a quarter.
- Pair it with Spam Score and Trust Flow. A high DA with a high Spam Score or a weak Trust Flow often points to bought or low quality links.
- Check the actual competitors. Look up the domains on page one for your keyword instead of chasing a target number.
- Don't buy links because a seller quotes DA. Sellers inflate DA with link schemes. Check the site's traffic, relevance and Trust Flow too.
If you're vetting a list of guest post sites or link prospects, the bulk domain authority checker scores up to 10 domains at once for free and exports the table to CSV.
Common questions
Is domain authority a Google ranking factor?
No. Google has said it doesn't use Moz's Domain Authority or any similar third party score. DA is still useful because it is built from link signals that do correlate with rankings.
Who created domain authority?
Moz created Domain Authority and Page Authority. Other companies use different names for their own scores, such as Domain Rating at Ahrefs and Trust Flow at Majestic.
What is the lowest and highest domain authority?
The scale runs from 1 to 100. New websites start at 1, and only the most linked sites on the web, such as major platforms, reach the high 90s.
How often does Moz update domain authority?
Moz updates its link index continuously and recalculates DA on a regular cycle, so scores can shift every few weeks. Small changes between checks are normal.
Does domain authority affect traffic?
Not directly. More links from strong, relevant sites tend to raise both DA and rankings, which is why the two often move together. Raising DA through spam won't bring traffic.