What are referring domains?

Backlinks and referring domains side by side

Most people would rightly prefer site B's profile. A sitewide link placed in a template generates a backlink on every page of the linking site in one action. It reflects one decision by one site owner. Three hundred different sites linking reflects three hundred decisions.

Why the distinction matters

Search engines use links as evidence that other people find a page worth referencing. Repeated links from the same site are, at best, the same endorsement stated again. This is the reasoning behind a long-standing observation in SEO: the first link from a new site tends to be worth more than the fiftieth link from a site that already links to you.

Google does not publish how it weighs repeated links, so treat that as a working principle and not a formula. And the count is still only a count:

• Quality outweighs quantity. One link from a respected publication in your field can matter more than dozens from unrelated directories.
• Relevance matters. A link from a site about your topic is a clearer signal than one from a site about anything.
• Manipulated links do not count, or count against you. Google's spam policies cover buying links, large-scale exchanges and automated link creation; see unnatural links to your site.
• nofollow, sponsored and ugc links are usually listed in the totals by tools but generally pass no ranking credit.

How domains are counted

Tools differ, which is why numbers never match between them.

• Root domain or subdomain? Some tools count blog.example.com and shop.example.com as one referring domain, others as two. Hosted platforms where each user has a subdomain make this a real difference.
• Live or historical? A link that has since been removed may or may not be counted.
• Crawl coverage. Every tool sees only the part of the web it has crawled.
• Filtering. Some exclude links they judge to be spam.

Compare trends within one data source, not absolute figures across sources.

Finding yours without paid tools

Google Search Console has the data Google itself is willing to show. Open Links, then Top linking sites under External links. Each row is a referring domain, with the number of linking pages and the number of your pages it targets. Click a domain to see which of your pages it links to. The Export external links button downloads the list.

Useful things to do with it:

1. Sort by linking pages to find sitewide links. A domain with thousands of linking pages to one target is a template link.
2. Look at which of your pages attract the most domains. Those are your strongest pages, and good places to add internal links to pages that need help.
3. Watch for sudden changes. A burst of unfamiliar domains is usually harmless spam that Google ignores. Our note on the disavow tool explains when action is warranted, which is rarely.
4. Check for lost links after a migration. If a strong linking domain points at a URL that now returns 404, redirect that URL.

Growing the number honestly

Referring domains grow when separate people have separate reasons to link. That comes from things worth referencing: original data, tools, clear explanations, well-documented products, and being known in your field. Tactics that produce many links from few sources, or many low-quality domains quickly, move the metric without moving what it is meant to measure. Our page on how to rank without backlinks covers what to do when link acquisition is slow.

On WordPress, the cheapest protection for the links you already have is a 404 log: inbound links to deleted or renamed pages show up there. Hydrogen SEO's 404 monitor records those requests so you can redirect them and keep the value of each linking site.