Referring domains
Also called: referring domain, linking domains, linking root domains, ref domains
Definition
Referring domains are the unique websites that link to a page or site at least once. Ten links from one site count as one referring domain, which makes it a better measure of link breadth than total backlinks.
A referring domain is a website that links to you. Count the sites, not the links: if the New York Times links to your page twice, that is two backlinks but one referring domain. Add a link from Forbes and you have two referring domains.
How it works
Referring domains are a metric from SEO tools, not from Google. Ahrefs defines them as domains from which the target site or page has one or more backlinks. Tools crawl the web, record links and group them by source domain.
Why the distinction matters: one site can generate thousands of links with a sitewide footer or blogroll. Those inflate backlink counts without adding much. Referring domains show how many different sites chose to link to you, which is closer to what links are supposed to signal.
Most keyword difficulty scores are built on referring domain counts of the pages already ranking. Third-party authority scores such as domain authority use them heavily too.
Why it matters for marketers
Referring domains are a quick health check:
- Growth: are new sites linking to you each month?
- Gap: how many referring domains do the pages outranking you have?
- Quality: are they relevant sites in your space, or random directories?
They are also a spam warning sign. A sudden spike of referring domains from unrelated, low-quality sites can mean someone sold you a link package. Google's spam policies define link spam as links created primarily to manipulate rankings, including buying links and low-quality directory links.
Example
Page A has 1,200 backlinks from 15 referring domains, most from one partner's footer. Page B has 90 backlinks from 60 referring domains, each a different blog or publication that mentioned it in an article. Page B usually has the stronger link profile, despite fewer total links.
How it plays out on Reddit
Reddit itself counts as one referring domain no matter how many threads link to you. That is one reason Reddit is a poor link-building channel and a strong visibility channel. Reddit threads rank for buying queries and are the most-cited domain in AI search in Peec AI's March 2026 US data. Being discussed there helps people find you; it does little for your referring domain count.
Where Reddit can lead to referring domains: writers, newsletter authors and bloggers read Reddit for ideas and sources. A useful answer or a genuinely interesting post can lead to a write-up that links to you from a new domain. That happens because the content was worth citing, not because you asked for it.
Common mistakes
- Reporting backlinks instead of referring domains. The bigger number is usually the less useful one.
- Buying "high DR" links. Paying for links to manipulate rankings is link spam under Google's policies.
- Ignoring relevance. Twenty referring domains in your niche beat two hundred unrelated ones.
Frequently asked questions
What is a good number of referring domains?
There is no universal target. Compare against the pages ranking for your target queries; that is the bar you need to meet.
Do referring domains matter more than backlinks?
They are usually a better signal of link breadth, because they count unique sites rather than repeated links from the same site.
How do I find my referring domains?
Use an SEO tool with a link index, such as Ahrefs, Semrush or Moz. Google Search Console's Links report also lists top linking sites.