Referring domains vs backlinks: which number matters
A backlink is one link to your site. A referring domain is one website that links to you, however many times. Referring domains are the better number to track, because the first link from a new site says more than the fiftieth from the same one.
In short
- A backlink is a single link from another site, and a referring domain is a unique website with at least one backlink to you, so 100 links from one site count as one referring domain.
- Ahrefs' January 2025 study of one million keywords found referring domains correlate with rankings at 0.255, against 0.248 for raw backlinks.
- The same study put Domain Rating at 0.131, a weaker correlation than a plain count of referring domains.
- A single sitewide footer link can add thousands of backlinks and only one referring domain, which is why backlink totals mislead.
- Every tool crawls its own copy of the web, so referring domain counts differ between Ahrefs, Semrush, Majestic and Google Search Console.
A backlink is one link from another website to yours. A referring domain is one website that links to you, no matter how many times. If a blog links to you from 100 different pages, you have 100 backlinks and one referring domain.
The number that matters more is referring domains. Each new site that links is a separate decision by a separate publisher. The hundredth link from the same site adds little to what the first one already said.
The two definitions
| Term | What it counts | Also called | Example |
|---|---|---|---|
| Backlink | Every individual link pointing to your site | Inbound link, inlink | One blog links to you in 100 posts: 100 backlinks |
| Referring domain | Each unique website with at least one backlink to you | Linking root domain | The same blog: 1 referring domain |
| Referring page | Each unique page that links to you | Linking page | The same blog: 100 referring pages |
| Referring IP or subnet | Each unique server address or address block that hosts linking sites | C-class | Used by tools to spot networks of sites hosted together |
A single backlink lives on a page, and a page lives on a domain. Tools report all three levels. The domain level is the one most link builders plan and report by.
Why referring domains say more
The data. Ahrefs studied one million US keywords and published the results in January 2025. The number of referring domains correlated with rankings at 0.255. The raw number of backlinks came in at 0.248. The gap is small, but it points the same way as the theory.
The theory. Link analysis treats a link as an endorsement. Fifty endorsements from the same person are worth less than endorsements from fifty people. The documentation that leaked from Google in May 2024 includes a field that records several links from the same source to the same target, according to analyses of the leak. Analysts read that as support for diminishing returns from repeated links on one domain. The field is documented. Its use and weight are not confirmed.
The practice. Backlink counts are easy to inflate and referring domains are harder. One site adding you to its footer can add thousands of backlinks overnight.
Correlation is not cause. Pages that rank well are seen by more people and attract more links, so some of the relationship runs the other way.
What inflates a backlink count
When backlinks far outnumber referring domains, one of these is usually the reason.
- Sitewide links. A link in a footer, sidebar or template appears on every page of the site. Sitewide and footer links explains when that is a problem.
- Pagination and archives. One article can appear on tag pages, category pages and date archives, and each copy counts as a backlink in a tool.
- Syndication. A press release or article copied across a network creates many links with little independent value.
- Automated spam. Scrapers and comment bots can create large numbers of links that Google is designed to ignore.
A ratio of backlinks to referring domains that jumps suddenly is worth a look. Open the tool’s report, sort by links per domain and see which sites are responsible.
When more links from the same domain still help
Diminishing returns do not mean zero. Three cases are worth having.
- Links to different pages. A second link from the same site to a different page of yours brings value and anchor text to a page that had none from that source.
- Links that send readers. A publication that covers you often keeps sending visitors and keeps your name in front of its audience.
- Fresh editorial mentions. Repeated coverage in the same outlet is what a real relationship with a journalist looks like. It is the normal result of good press work.
What adds almost nothing is the same link repeated across every page of one site.
Not all referring domains are equal
Counting domains is better than counting links, and it is still only counting. One link from a publication your customers read can outweigh fifty from sites nobody visits.
Three refinements make the number more honest.
Followed referring domains. Tools can filter out domains whose links all carry nofollow, sponsored or ugc. In the Ahrefs study, followed referring domains correlated at 0.250 and all referring domains at 0.255. The two are too close to separate, so report both.
Quality of the domain. The same study found Domain Rating correlated with rankings at only 0.131, weaker than a plain count of referring domains. A score on its own is a poor filter. Domain Authority vs Domain Rating explains what those scores measure. Real organic traffic and topical fit say more, and how to vet a publisher gives the checks.
Independence. Fifty domains owned by one operator and hosted together are closer to one source than fifty. That is why tools report referring IPs and subnets, and it is one of the footprints that exposes a private blog network.
Why every tool shows a different number
Google does not publish a full list of your links. The Links report in Search Console shows a sample. Ahrefs, Semrush, Majestic and Moz each run their own crawler and keep their own index, so each sees a different slice of the web.
Tools also differ in how they count: whether subdomains are separate domains, how long a lost link stays in the total, and whether redirects are included. Pick one tool and compare like with like over time. Our desk review of Ahrefs and the wider backlink tools comparison cover the differences.
Counts also fall. An Ahrefs study dated February 2024 found that about two thirds of links to sites over the previous nine years were dead. A referring domain total should be read as live domains now, not as every domain that ever linked.
Which number to use for what
| Task | Number to use |
|---|---|
| Reporting link building progress | New referring domains per month, with followed domains shown separately |
| Sizing the gap to a competitor | Referring domains to the page that ranks, compared with yours |
| Checking for a spam pattern | Backlinks per referring domain, and the anchors on the largest sources |
| Checking for a network | Referring IPs and subnets |
| Finding lost value | Lost referring domains, and backlinks pointing to broken pages |
The second row is the one that sets budgets. How many backlinks you need shows how to turn it into a target.
Where to go next
Read how to track backlinks to set up monitoring. Definitions of referring domain, linking root domain and related terms are in the glossary.
Common questions
What is a referring domain?
It is a website that links to yours at least once. Tools also call it a linking root domain. If a site links to you from 300 pages, that is 300 backlinks and one referring domain.
Which is more important, backlinks or referring domains?
Referring domains. In Ahrefs' January 2025 study they correlated with rankings slightly better than backlink counts, and the model behind link analysis gives less to each extra link from the same site.
Why do I have far more backlinks than referring domains?
Usually because one or more sites link to you from every page, through a footer, sidebar or template. It can also come from one site citing you in many articles.
Is it bad to get many links from the same domain?
Not in itself. Repeated editorial links from a site that covers you often are normal. A sitewide link with a keyword anchor is different, because Google's spam policies name widely distributed footer and template links.
How many referring domains do I need?
There is no fixed number. Compare the page you want to rank with the pages that already rank for that search, and count the referring domains to each.
