Referring domains are the unique websites that link to your site or to a specific page. If a news site links to you ten times, that's ten backlinks but only one referring domain.
For businesses, referring domains are a more honest measure of reach than raw backlink counts. Ten different, relevant sites vouching for you says more about your reputation than one site linking to you a hundred times, and that breadth of independent mentions also helps search engines and AI tools see your brand as established.
What are referring domains?
A referring domain is a domain that contains at least one link to your website. Ahrefs' help center puts it this way: referring domains are domains from which the target website or page has one or more backlinks. Its example: if a page has two backlinks from the New York Times, it still has one referring domain.
So a backlink is a single link, and a referring domain is a unique site that sends one or more of those links. Most SEO tools report both numbers side by side.
Tools differ in how they count. Some count subdomains separately, and some group them under a root domain. Google Search Console's Links report groups linking sites by root domain, stripping subdomains and protocols, but treats different top-level domains, such as example.com and example.de, as separate sites.
Why referring domains matter
Links still matter to Google. Google's guide to its ranking systems says Google has systems that understand how pages link to each other, and that PageRank continues to be part of its core ranking systems. Links from many independent sites are a natural sign that a site is worth referencing.
Breadth beats repetition. Extra links from a domain that already links to you add less new information than a link from a site that has never mentioned you. That's why many SEOs track referring domains as a primary link metric.
Studies show a correlation with traffic. Ahrefs' 2023 search traffic study found that pages with more referring domains tend to get more search traffic and rank for more keywords. Ahrefs itself cautions that correlation does not imply causation, so treat this as direction, not proof.
They support AI visibility. AI search tools draw on web sources, and independent coverage across many sites gives a brand more chances to appear in the sources those tools read. Referring domains are one rough proxy for that breadth of off-page presence.
How referring domains work
Counting unique sources
Tools crawl the web, record links pointing to your site, then group them by the linking domain. Each domain counts once, however many links it contains. Because every tool crawls a different slice of the web, your count will differ between Ahrefs, Semrush, Moz and Search Console.
Quality signals that tools add
Third-party tools also score referring domains with metrics like Domain Rating or Authority Score. These are tool-specific estimates, not Google metrics. See domain authority for how to use them carefully.
Followed and nofollowed links
Some referring domains link with rel="nofollow", rel="sponsored" or rel="ugc". Google treats these as hints rather than strict rules. Search Console's Links report doesn't say whether a link is nofollowed, while most third-party tools let you filter by attribute. See link attributes.
How to grow referring domains
- Publish things people cite. Original research, data, tools and clear explainers attract links from many sites over time.
- Use digital PR. Newsworthy stories can earn coverage from multiple publications at once. See digital PR.
- Look at competitor gaps. Find sites that link to several competitors but not you. They already cover your topic.
- Reclaim mentions. Ask sites that mention your brand without linking to add a link.
- Fix broken links pointing to you. Redirect old URLs that still have links to their best current equivalents.
- Prioritize relevance. A link from a respected site in your industry is worth more than many links from unrelated sites.
Common mistakes and misconceptions
"More referring domains always means higher rankings." Relevance, quality and content still matter. A smaller number of strong, relevant sites can outperform a large number of weak ones.
"Any new domain is a win." Links from spammy directories or link networks add risk, not value. Google's spam policies list buying links for ranking purposes and low-quality directory links as link spam.
"Every tool should show the same number." Each tool has its own crawler and counting rules. Compare trends within one tool rather than numbers across tools.
"A drop in referring domains is a penalty." Sites delete pages, and tools recrawl and clean their indexes. Small swings are normal. Look at whether important links were lost.
Referring domains vs. backlinks
Backlinks count every individual link. Referring domains count the unique sites behind those links. A site with 5,000 backlinks from 40 domains has a narrow link profile, while a site with 800 backlinks from 300 domains has much broader support. Most SEOs look at referring domains first for that reason.
How Butter approaches referring domains
At Butter, we report on what actually moves the needle, like referring domains, organic visibility and traffic, through monthly delivery reports. We treat new referring domains as a reputation project, not a volume game. The GEO plan includes one AI-crawlable content citation and backlink each month, and the GEO+SEO plan adds one quality backlink each month on top of that.
For brands that want more coverage, our Public Relations add-on focuses on earned media. We don't buy links from networks, and we don't promise that a specific number of placements will move a ranking. Our SEO service page explains how links fit into the rest of the program.
Frequently asked questions
What is the difference between a backlink and a referring domain?
A backlink is one link from another site to yours. A referring domain is a unique website that links to you one or more times. Ten links from one site count as one referring domain.
How do I check my referring domains?
Google Search Console's Links report shows top linking sites, grouped by root domain. Third-party tools like Ahrefs and Semrush show fuller lists with extra filters, though each tool's count differs.
How many referring domains do I need?
There's no fixed number. It depends on your competitors and topic. Compare your profile with pages that rank for your target keywords, and focus on relevant, quality sites.
Do nofollow referring domains count?
Google treats nofollow as a hint, so these links may still carry some value. They can also send referral traffic and build brand visibility, including in sources AI tools read.