Quick answer
Domain Authority (DA) and Domain Rating (DR) both try to estimate how "strong" a website's backlink profile is on a 0–100 scale — but they're not the same metric. DA is Moz's proprietary score; DR is Ahrefs' equivalent. They use different data sets and different formulas, so the same site can (and usually does) show a different DA than DR. Neither is an official Google ranking factor — both are third-party estimates of authority, useful for comparison, not gospel.
The core confusion: two different companies, two different scores
DA and DR get used almost interchangeably in casual link-building conversation, which causes real confusion when someone says "this site is DA 50" and someone else assumes that number came from Ahrefs. It didn't — DA is specifically Moz's metric, calculated from Moz's own link index (Moz Link Explorer). DR is specifically Ahrefs' metric, calculated from Ahrefs' own crawl and link index.
Since Moz and Ahrefs crawl the web independently and weight signals differently, they arrive at different numbers for the same site — sometimes close, sometimes 15–20 points apart. Neither company shares its exact formula publicly, so there's no way to mathematically convert one score to the other.
| Domain Authority (DA) | Domain Rating (DR) | |
|---|---|---|
| Created by | Moz | Ahrefs |
| Scale | 0–100 (logarithmic) | 0–100 (logarithmic) |
| Based on | Moz's own link index | Ahrefs' own link index |
| Official Google metric? | No | No |
| Best used for | Relative comparison within Moz's ecosystem | Relative comparison within Ahrefs' ecosystem |
Why both scales are logarithmic, not linear
Neither DA nor DR moves evenly — going from 20 to 30 is far easier than going from 70 to 80. This is by design: both scores are logarithmic, meaning each additional point requires an increasingly large jump in linking-root-domain quality and quantity. A site with DR 80 isn't "twice as strong" as a DR 40 site — it's exponentially stronger, which is part of why prices for backlinks on very high-authority sites climb so steeply (see our realistic backlink pricing guide for how this plays out in actual market rates).
Which one should you actually use?
In practice, the answer is usually "whichever tool you already have access to" — both are directionally useful for the same purpose: quickly comparing the relative authority of two or more sites before digging into the details. A few practical notes:
- Ahrefs' DR is more commonly cited in the backlink marketplace and link-building world specifically, likely because Ahrefs' link index is widely regarded as one of the largest and most frequently refreshed.
- Moz's DA is more commonly cited in broader SEO/content marketing contexts, partly due to Moz's long history as one of the first mainstream SEO toolsets.
- Neither should be your only filter. A site with strong DA/DR but no real organic traffic is often a red flag rather than a reassurance — see our guide on spotting a spammy backlink site for what that pattern usually means.
Why a site's DA and DR can differ significantly
It's completely normal — even expected — for the same site to show meaningfully different DA and DR numbers. A few real reasons this happens:
- Different crawl coverage. Neither Moz nor Ahrefs has indexed literally the entire internet; each has blind spots the other doesn't.
- Different update frequency. One index might have refreshed a site's backlink profile more recently than the other, especially after a recent link spike or loss.
- Different weighting of link quality. Both systems try to discount spammy or low-quality links, but they don't use identical criteria for what counts as "low quality."
None of this means one score is "wrong" — they're simply two independent estimates built on different underlying data.
How this applies when buying or vetting backlinks
If you're evaluating a site to buy a link from, or to exchange with, the practical takeaway is: don't compare a DA number from one seller against a DR number from another and assume they're equivalent. Always compare like for like — DA-to-DA, or DR-to-DR — and where possible, verify the number yourself rather than trusting a screenshot, since claimed metrics are one of the easiest things to fake in an unmoderated backlink marketplace.
This is also why a proper site-vetting checklist treats DA/DR as one input among several — traffic, niche relevance, and content quality all matter alongside whichever authority score you're looking at.
Frequently Asked Questions
Is a DR 50 site the same authority as a DA 50 site? Not necessarily. Because the two metrics are calculated independently, a DR 50 and a DA 50 site could have meaningfully different actual link profiles. Treat them as separate scales, not interchangeable numbers.
Which is harder to increase, DA or DR? Both follow a similar logarithmic difficulty curve — the higher the existing score, the harder each additional point becomes. Neither is inherently "easier" to move; it depends on how competitive the site's existing link profile already is.
Can I check DA and DR for free? Yes, several tools offer limited free lookups for both. See our full breakdown in how to check Domain Authority for free.
Does Google use DA or DR to rank pages? No — neither is a Google ranking factor. Both are third-party estimates built by Moz and Ahrefs respectively, useful as a proxy signal for comparison, not something Google's algorithm directly consults.
Is there a third major authority metric besides DA and DR? Yes — Semrush has its own "Authority Score," built on its own independent data set, adding a third (also non-interchangeable) option into the mix.
The bottom line
DA and DR are both useful, legitimate tools for estimating a site's relative link authority — but they're built by different companies on different data, and treating them as interchangeable is a common beginner mistake. When comparing sites, stay consistent about which metric you're using, verify claimed numbers where you can rather than trusting screenshots, and remember that authority is only one input into whether a backlink is actually worth acquiring.
