What Is Domain Authority (DA)?

How Domain Authority Works

Domain Authority is Moz’s answer to a practical question SEOs ask constantly: if I go up against this domain, how likely is it to outrank me? Rather than measure a site’s current traffic or count its links, DA predicts competitive ranking ability and expresses that prediction as a number from 1 to 100. The higher the score, the more likely — in Moz’s model — that the domain ranks well across search results.

That framing matters because it makes DA a comparative tool by design. Moz is explicit that Domain Authority is best used to compare one site’s strength against another’s, or to track a single site’s trend over time, not as an absolute grade. A DA of 50 is meaningful only next to the DA of the sites you are actually competing with. In an easy niche, 50 might dominate; in a crowded one, it might not crack the first page.

Because the score is logarithmic, the effort to move it is wildly uneven. Growing from DA 20 to DA 30 is comparatively quick; pushing from DA 70 to DA 80 demands an order of magnitude more high-quality backlinks. Chasing the top of the range is a game of diminishing returns, which is why experienced practitioners watch the direction of travel rather than obsess over the exact digit.

What Goes Into the Score

Moz calculates DA with a machine-learning model, and the model is trained against real search results — it is tuned to predict which domains actually appear in Google’s rankings. The inputs Moz has described feeding into that model include:

• Linking root domains — the count of unique domains pointing to the site, the heaviest lever.
• Total links — the overall volume of backlinks, including multiple links from the same domain.
• MozRank and MozTrust — Moz’s own link-authority and link-trust scores.
• Spam Score adjustment — a downward correction for profiles that look manipulative.
• Anchor-text distribution — the mix of anchor text across the backlink profile.

Because a machine-learning model sits in the middle, there is no clean hand-computable formula. Moz periodically retrains it to stay aligned with how Google actually behaves, which means the whole scale can shift underneath you even when your own site hasn’t changed.

Example of Domain Authority

The clearest documented moment in DA’s history is the Domain Authority 2.0 relaunch, which Moz rolled out in March 2019. It is a useful worked example because Moz described exactly what changed and why, and the reasoning reveals what the metric really is.

DA 2.0 was a full retraining of the model rather than a cosmetic tweak. Moz rebuilt it to better predict rankings in the face of Google’s evolving algorithm, strengthening how the model handles manipulative link profiles through an improved Spam Score adjustment and refining its use of signals like anchor-text distribution and linking root domains. Crucially, Moz warned users ahead of the switch that individual DA scores might rise or fall on launch day — not because those sites had changed, but because the model had. That single fact is the whole lesson: DA is a prediction produced by a model, and when the model is recalibrated, the predictions move.

The 2.0 change also sharpened a point Moz has always made and that the Moz Domain Authority documentation still stresses — DA is a relative, comparative metric. After a retraining, the only honest way to read your score is against your competitors on the same day, because everyone was re-scored on the same new model at once.

And it is worth stating plainly what DA is not. It is not a Google ranking factor. Google’s John Mueller has publicly rejected the idea that Google uses a domain authority signal of this kind. DA can correlate with rankings because Moz deliberately trains it against real search results, but correlation is the mechanism, not causation. Raising DA does not push a button inside Google’s algorithm.

Domain Authority vs Domain Rating

Domain Authority and Domain Rating are the two metrics people confuse most, because both put backlink strength on a roughly 0–100 scale. They are not the same measurement and their numbers must never be swapped.

The distinction is real: DA is trained to predict rankings, so it folds in signals like spam and anchor text, while DR is a purer measure of link strength. A site can score high on one and lower on the other. Choose the metric your team standardizes on, and only ever compare it to itself and to direct competitors.

Frequently Asked Questions

The Bottom Line

Domain Authority is Moz’s forecast, on a 1–100 scale, of how competitively a whole site could rank based on its link signals. It is a predictive, comparative model — useful for sizing up domains against one another — not a measurement of quality and not a number inside Google. Read it as a relative weather report on link strength, and judge it against your actual competitors.