A backlink is one link from one page to another, and a referring domain is one unique website that links to you, so fifty links from a single site count as fifty backlinks and one referring domain. The two numbers measure different things: backlinks measure volume, and referring domains measure breadth. This page defines both terms, explains why the counts diverge, shows where to read them and states which one the authority metrics weigh.
What is the difference between referring domains and backlinks?
A backlink is a single link from one web page to another, and a referring domain is a unique website that has at least one backlink to yours. One referring domain supplies one or many backlinks. The referring-domain count therefore never exceeds the backlink count.
| Measure | What it counts | Example |
|---|---|---|
| Backlink | Each link from a page to your site | Three links from one article count as 3 |
| Referring domain | Each unique website that links to you | Three links from one site count as 1 |
The link is the unit for backlinks, and the website is the unit for referring domains.
Which metric matters more, referring domains or backlinks?
Referring domains are the primary measure, because Moz lists the number of linking root domains among the factors behind Domain Authority and Ahrefs calculates Domain Rating from the linking domains of a whole website, while a backlink total also counts repeated links from one site.
Ahrefs describes Domain Rating as the backlink strength of a domain, with link value shared across the domains each site links to. Both descriptions point at the site-level count. A profile with 400 backlinks from 12 domains carries less breadth than a profile with 60 backlinks from 50 domains. Ahrefs reports URL Rating for single pages, so track both numbers and use referring domains as the primary measure.
Why do the two numbers differ?
The two numbers differ because one site places many links to the same target, through sitewide elements, repeated mentions or multiple pages. A larger gap between the counts signals more repetition per site, and a smaller gap signals links spread across many independent sites.
- Footer and sidebar links appear on every page of the linking site, so one site produces hundreds of backlinks.
- Blogroll and partner-page links repeat across a site’s templates.
- Multiple articles on one site mention and link to the same source.
- Profile and comment links stack up on forums and community platforms.
Read the ratio of backlinks to referring domains as a diagnostic, not a goal. The bands below are our working heuristic, not a Google or vendor threshold.
| Backlinks per referring domain | Reading |
|---|---|
| 1 to 3 | Typical of editorial links earned across many sites |
| 4 to 10 | Inspect the top linking sites for sitewide or repeated links |
| Above 10 | Sitewide or footer links dominate the profile |
The guide to profile composition shows how the ratio fits into a full health check.
Where do you see both numbers?
Google Search Console shows top linked pages, top linking sites and top linking text for a verified property, and third-party tools report both backlink and referring-domain counts from their own indexes. The Search Console report does not show whether a link carries nofollow.
Counts differ from tool to tool because each vendor crawls the web differently, as Ahrefs notes about its own numbers. Compare a site against competitors inside one tool, not across tools. The authority metric lookup is not a count tool, but it reports Domain Rating and Domain Authority for many domains in one run, which gives a quick read on the sites behind the referring-domain count.
How do you grow the referring-domain count?
Grow the referring-domain count by earning links from new sites, because every additional link from a site already in the profile adds a backlink and no new domain. The method is to widen the source list, not to deepen links on the same hosts.
Set a target per month in new referring domains, as the guide on how many backlinks you need shows, and choose placements that sit on different hosts. The overview of earning links compares the methods, and the guide to anchor ratios keeps the anchors across new domains varied. Backlink Agency builds links on separate real sites and reports each host in the order sheet; the raise Ahrefs DR service applies the same approach to a Domain Rating goal.
The link metrics guides hold the full set of authority-metric definitions, and Domain Authority explained covers the Moz side of the comparison.
Related: competitor domain gap rebuilds, hand-built link order page, and ways to raise site authority.