Domain Authority (DA) is one of the most widely used metrics in SEO — and it is a Moz invention. Understanding what DA is, how to check it for free, and when paid access is necessary helps you decide whether a Moz Pro subscription is right for your workflow.
Domain Authority is a proprietary metric developed by Moz. It scores a website's likelihood of ranking well in search engine results on a scale of 1 to 100. Higher scores indicate greater ranking potential.
DA is calculated using a machine learning model that incorporates multiple link-related signals from Moz's web index: the number and quality of linking root domains, the authority of those linking domains, and the overall link profile health. A brand new domain starts at DA 1. The world's most authoritative sites (Wikipedia, Google, etc.) approach DA 100.
Important: DA is not a Google ranking factor. It is a third-party proxy metric. Google has its own PageRank algorithm (not publicly disclosed) and hundreds of additional signals. DA correlates with rankings because good backlinks are a ranking factor — but the DA score itself is Moz's interpretation, not Google's.
Install MozBar from the Chrome Web Store and browse to any website. DA and PA are displayed in the toolbar automatically. Also overlays DA on Google search results. No query limits — check as many sites as you want.
Go to moz.com/link-explorer and enter any domain. Shows DA, linking domains, top pages, and more. 10 queries per month with a free Moz account — sufficient for occasional competitor checks.
Several third-party tools provide DA data using the Moz API, including bulk DA checkers. Quality and freshness vary. These are using Moz's data under the hood — always check data date.
| Metric | Provider | Scale | Basis | Industry usage |
|---|---|---|---|---|
| Domain Authority (DA) | Moz | 1–100 | Link profile quality and quantity (Moz index) | Most widely referenced in client conversations |
| Domain Rating (DR) | Ahrefs | 0–100 | Backlink quality (Ahrefs index — largest) | Preferred by link builders using Ahrefs |
| Authority Score (AS) | Semrush | 0–100 | Backlinks + organic traffic + spam signals | Used in Semrush reports |
| Use case | Free tools sufficient? | Recommended |
|---|---|---|
| Checking your own site's DA occasionally | Yes — MozBar or Link Explorer free | MozBar (free) |
| Checking competitor DA during research | Yes — 10 free queries/month covers casual use | Link Explorer free tier |
| Link prospecting (checking 50+ domains/month) | No — 10 free queries insufficient | Moz Pro Standard ($79/mo annual) |
| Monitoring client DA over time | No — requires ongoing access | Moz Pro Standard ($79/mo annual) |
| Bulk DA checks (500+ domains) | No — requires API or paid plan | Moz Pro Large + API ($239/mo annual) |
Moz Pro Standard gives unlimited Link Explorer access for $79/mo on annual billing.