Domain Authority (DA) is a third-party metric developed by Moz that predicts how likely a whole website is to rank in search results, expressed on a scale from 1 to 100. In SEO, and specifically in the area of links & authority, DA serves as a quick comparative indicator of a domain’s backlink strength, used for competitor analysis, prospecting and reporting.
Domain Authority is not used by any search engine. Google does not compute or consult it, and a change in DA neither causes nor guarantees a change in rankings. Its value lies in relative comparison between sites, measured with the same tool at the same time.
How Domain Authority is calculated
Domain Authority is calculated by a machine learning model trained to predict how often a domain appears in search results, using data from Moz’s own link index. The model weighs link signals such as the number of linking root domains, the quality of those linking domains and the overall link profile, and outputs a single score.
The scale is logarithmic, not linear. Moving from DA 20 to DA 30 is far easier than moving from DA 70 to DA 80, because each step at the top requires a much larger increase in high-quality links. Since a 2019 model revision, the calculation also tries to discount spam and manipulative link patterns.
The table lists the main inputs and their effect on the score.
| Input | Effect on DA | Comment |
|---|---|---|
| Linking root domains | Strong positive | Many distinct sites count more than many links from one site |
| Quality of linking domains | Strong positive | Links from authoritative domains weigh more |
| Spam and link pattern signals | Negative or neutral | Suspicious patterns are discounted |
| Total number of links | Weak positive | Repeated links from one domain add little |
| Ranking data in the model | Calibration only | Used to train the prediction, not as a direct input |
Interpreting Domain Authority values
Domain Authority values should be interpreted comparatively, never absolutely. A score of 35 is weak for a national news publisher but strong for a local plumbing company, because DA has meaning only against the sites competing for the same queries.
| DA range | Typical sites | Practical meaning |
|---|---|---|
| 1-20 | New sites, small blogs, local businesses | Few authoritative links yet |
| 20-40 | Established small and mid-sized sites | Competitive in niche and local searches |
| 40-60 | Strong specialist sites and regional media | Competitive for many mid-volume topics |
| 60-80 | Major brands and national publishers | Broad link authority |
| 80-100 | Global platforms and top media | Exceptional, very rare |
Scores also fluctuate without any change on the site. Moz updates its index and recalibrates the model, so a competitor gaining very large numbers of links can shift scores across the scale. Short-term drops of a few points are often noise and should be judged against competitors measured on the same date.
Domain Authority compared with similar metrics
Domain Authority is one of several proprietary authority metrics, each built from a different link index and formula. The scores are not interchangeable, and comparing a DA from one tool with a Domain Rating from another is meaningless.
| Metric | Provider or origin | What it measures |
|---|---|---|
| Domain Authority | Moz | Predicted ranking potential of a domain |
| Page Authority | Moz | Same prediction for a single page |
| Domain Rating | Ahrefs | Relative strength of a domain’s backlink profile |
| Authority Score | Semrush | Composite of links, traffic and spam signals |
| PageRank | Google, internal | Link-based importance used inside ranking systems |
The essential distinction is with PageRank, which Google does use internally but no longer displays publicly. DA attempts to approximate the kind of link equity that PageRank represents, yet it is calculated from a smaller crawl and an independent model, so it remains an estimate from outside.
Using Domain Authority in practice
Domain Authority is most useful as a screening and benchmarking tool. It helps teams quickly sort large lists of domains and track the general trend of their own link building, as long as decisions are confirmed with deeper analysis.
| Use case | Suitability | Reason |
|---|---|---|
| Comparing competitors in one niche | Suitable | Same tool and date make scores comparable |
| Pre-screening link prospects | Suitable with checks | Filters obvious low-quality sites quickly |
| Tracking link building trends | Suitable over months | Shows whether authority grows |
| Valuing a link by DA alone | Unsuitable | Ignores relevance, placement and traffic |
| Promising rankings from DA growth | Unsuitable | Search engines do not use the metric |
| Pricing links or guest posts by DA | Unsuitable | Encourages manipulation and paid links |
When evaluating a linking site for guest posting or broken link building, topical relevance, real organic traffic and editorial standards matter more than the score. A relevant site with DA 25 often sends better signals and visitors than an unrelated site with DA 70.
Limitations and manipulation risks
The main limitation of Domain Authority is that it measures link popularity, not content quality or relevance. It reflects one tool’s view of the link graph and therefore misses many factors that real ranking systems consider.
- Inflated scores exist. Link farms and expired domains with old links can show high DA but carry toxic backlinks.
- Index coverage differs. Links that Moz has not crawled do not count, even if search engines know them.
- Subdomains share the root score. Platforms hosting user sites can give weak pages a misleading DA.
- DA ignores nofollow nuances. Sponsored and UGC link attributes are treated differently by search engines.
- Chasing DA distorts strategy. Effort shifts from useful content to score-driven link acquisition.
For these reasons, experienced practitioners use DA as one data point among several, cross-checked with traffic estimates, ranking keywords and a manual review of the linking pages.
The simple explanation
Domain Authority is a score from 1 to 100 that a software company calculates to estimate how strong a website is in search, mostly by looking at which other websites link to it. More links from respected sites mean a higher score.
It works like an unofficial credit rating. It gives a quick sense of reputation and is handy for comparing similar websites, but the search engine does not look at it. A high score is a sign of a strong link profile, not a guarantee of top rankings.
How it is used in practice
A digital agency plans link outreach for a regional bicycle shop with DA 18. Its main local competitors score between 24 and 31, which suggests that the shop’s gap is mainly in authoritative links rather than in content. The agency compiles 300 potential partner sites and uses DA to filter out obvious low-quality domains below 10.
It then reviews the remaining sites manually for local relevance and real traffic, prioritizing cycling clubs, local news and event organizers over high-DA but unrelated directories. After nine months the shop gains about 40 relevant linking domains, its DA rises to 27 and, more importantly, its local rankings improve for repair and bike sale queries.