Domain Authority is a proprietary metric created by Moz, scored from 0 to 100, that estimates a website's ranking strength relative to competitors. It's calculated using a machine-learning model trained on Google's actual rankings, evaluating factors like the number of linking root domains, total backlinks, MozRank, MozTrust, and domain age. A site with DA 60 typically outranks one with DA 30 if all else is equal, but DA itself isn't a ranking factor—Google has never confirmed using it. What matters is that DA correlates with the signals Google does care about: authoritative backlinks from diverse, trusted sources. A site earning links from CBC, Globe and Mail, or university domains will see DA rise because those links carry editorial weight and topical relevance. Conversely, buying 500 spammy directory links might bump DA briefly but won't help rankings and often triggers penalties. DA is logarithmic, so moving from 20 to 30 is easier than 70 to 80. Most small businesses sit between 10 and 40. Local Ottawa service businesses often land around 15–25 DA, while established agencies or national brands push 50+. Obsessing over DA alone is a mistake—focus on acquiring links that drive referral traffic and topical authority in your niche. At Ottawa SEO, we track DA as one health indicator in our portfolio, but we prioritize link velocity, anchor text diversity, and whether backlinks come from pages that themselves rank. A single link from a DA 65 industry publication beats ten DA 25 blog comments. We also watch for DA inflation—sites that achieve high scores through link schemes but lack real editorial links collapse when Google's algorithm updates. Competitor tools like Ahrefs Domain Rating (DR) and Semrush Authority Score follow similar logic but use different datasets and formulas, so scores vary across platforms. Use DA for relative benchmarking and tracking progress over months, not as a pass-fail threshold. The goal is sustainable link equity from sources your target audience actually reads, which naturally lifts DA as a side effect. How Domain Authority Is Scored: The Algorithmic Mechanics Moz's scoring engine uses a machine-learning model that ingests their Link Explorer index—currently crawling over 40 trillion links—and compares your backlink profile against sites that actually rank well in Google. The model assigns weight to each linking domain based on its own authority, spam likelihood, and link neighbourhood quality. Your final score emerges from how closely your link graph resembles those of high-ranking domains in the training set. Because the model retrains periodically, your DA can shift without gaining or losing a single link. This recalibration happens roughly quarterly, which is why practitioners track DA trends over six-month windows rather than reacting to weekly fluctuations. What Makes Up Domain Authority: The Core Inputs Three primary data points feed the calculation. First, linking root domains—the count of unique websites pointing to you—carries the heaviest weight because Google's own systems reward link diversity. Second, total link count matters but with diminishing returns; ten links from one newspaper domain contribute less than ten links from ten separate publications. Third, MozTrust propagates from seed sites like government portals and major news outlets through outbound link chains, so earning a link from a site that itself links to .gov or .edu pages transfers trust more efficiently. Spam score acts as a dampener—domains flagged for thin content or link manipulation see their contributions discounted before your DA is tallied. Factors That Influence Domain Authority Over Time Link acquisition velocity is the most controllable lever. Steady month-over-month growth in referring domains signals organic editorial interest, whereas sudden spikes often correlate with link schemes and can trigger spam-score inflation. Anchor text variety also matters indirectly; a natural profile mixes branded anchors, naked URLs, and topical phrases, while over-optimised exact-match anchors depress trust signals. Domain age contributes modestly—Moz's model recognises that older domains have had more time to accumulate legitimate links—but a five-year-old site with a weak link profile still scores lower than a two-year-old site attracting authoritative coverage. Finally, your competitors' link-building activity influences your relative score; if rivals accelerate their efforts, your DA can stagnate even while your own link count grows. How Domain Authority Algorithm Works Behind the Scenes Moz's algorithm treats DA as a comparative ranking probability, not an absolute quality grade. It normalises scores so the distribution stays meaningful: a handful of sites cluster near 95-100, most small-business sites fall between 10 and 35, and the median hovers around 20. The model penalises thin link graphs more heavily at lower authority levels, which explains why new sites struggle to break DA 15 until they secure five to ten quality referring domains. Understanding this curve helps set realistic targets—aiming for three to five new referring domains per quarter is often more productive than chasing an arbitrary DA number. Frequently Asked Questions How domain authority is scored? Moz's machine-learning model compares your backlink profile—linking root domains, total links, and trust signals—against domains that rank well in Google. The comparison produces a 0-100 score updated roughly quarterly when the model retrains on fresh crawl data. What makes up domain authority? The main components are linking root domain count, total backlinks, MozRank, MozTrust inherited from authoritative seed sites, and a spam-score dampener that discounts low-quality link contributions. Factors that influence domain authority? Link diversity, acquisition velocity, anchor text naturalness, domain age, and competitor activity all shift your score. Earning links from sites that themselves link to trusted sources accelerates gains more than raw link volume. How domain authority algorithm works? The algorithm normalises scores across the web so most sites fall between 10 and 35. It weights unique referring domains heavily, discounts spammy links, and recalibrates periodically—meaning your DA can change even without new links.