Quick answer: Moz DA (Domain Authority) and Ahrefs DR (Domain Rating) both score a domain's link strength from 0–100, but they measure different things. DA is a machine-learned prediction of ranking ability built from many link signals; DR is a focused measure of how many strong domains link to you with dofollow links. Google uses neither. Use them to compare sites against each other — never as an absolute grade.

If you have ever looked the same website up in both tools and gotten DA 34 and DR 51, nothing is broken. The two numbers answer slightly different questions, from two different link databases, on two different scales. Here is what each one actually says — and the handful of ways these scores genuinely earn their keep.

What Moz DA actually measures

Domain Authority is a predictive model: Moz trains it on real Google results, asking which link-profile features best predict that one domain outranks another. Dozens of signals from Moz's link index feed it — linking root domains, link quality and spam scores, link patterns — and the output is calibrated so the whole web fits a 0–100 curve. Because the target is "ranking likelihood," DA absorbs Moz's judgment about which link features matter, and it gets re-tuned when the model updates — which is why DA sometimes jumps a few points overnight across the entire internet.

What Ahrefs DR actually measures

Domain Rating is deliberately narrower: it counts dofollow linking domains, weighted by their own DR, diluted by how many other sites each one links out to. That is the whole formula, more or less. No traffic estimates, no spam modeling, no ranking prediction — just recursive link equity, PageRank-style, on a logarithmic 0–100 scale. The logarithmic part matters: climbing from DR 10 to 20 takes a handful of decent links; climbing from 70 to 80 takes an order of magnitude more.

DR vs UR: the distinction most people miss

Ahrefs shows two scores, and the one everyone quotes is the less useful one for a specific ranking question. DR rates the domain; UR (URL Rating) rates the individual page's own backlinks. Pages rank in Google — domains do not — and in Ahrefs' own correlation studies UR tracks ranking position more closely than DR. Practical reading:

  • High DR, low UR page — the domain is strong but this page has few direct links. Beatable, even by a smaller site with a well-linked page.
  • Low DR, high UR page — someone built links straight to this URL. Harder to displace than the domain score suggests.

Why the numbers disagree — and which to trust

Moz DA Ahrefs DR
Measures Predicted ranking ability Dofollow linking-domain strength
Method Machine-learned, many signals Recursive link-equity formula
Link index Moz’s crawl Ahrefs’ crawl (among the web’s largest)
Updates Slower, model recalibrations Frequent, tracks new links quickly
Inflatable by spam Harder (spam signals modeled) Somewhat easier (dofollow counts)

"Which is more accurate" has an honest answer: neither, because there is no ground truth — Google publishes no authority score to check against. Ahrefs' bigger, faster index makes DR the better freshness signal; Moz's modeling makes DA the more conservative one. The scores agree on direction far more often than magnitude: a DR 60 site is almost always stronger than a DR 20 site, and DA will say the same thing in its own units.

How to use authority scores without fooling yourself

  1. Compare, never grade. "My DR is 22 and the sites ranking for my keyword are DR 15–30" is a real insight — the keyword is winnable. "My DA is 22, is that good?" has no answer.
  2. Same tool on both sides. Never compare your Moz DA to a competitor's Ahrefs DR — different scales, different indexes.
  3. Watch trend, not level. A score drifting up over months means the link profile is growing. A one-point wobble means the model recalibrated.
  4. Check the page, not just the domain. Before targeting a keyword, look at the UR (or Moz PA) of the actual ranking pages — that is the fight you are in.
  5. Remember what the score cannot see. Content quality, intent match, and on-page health decide most rankings under DR ~40. A technically clean store with sharp product-page SEO routinely outranks higher-authority domains whose pages are generic — which you can verify by tracking the rankings themselves, the only scoreboard that pays.

For a Shopify store, the order of operations follows from that last point: fix the on-page and technical layer first (it is fully in your control), publish content that answers real questions, and let authority compound. A free audit shows where the controllable half stands today.