Referring Domains vs Backlinks: Which Number Should You Track?
A client once sent me a screenshot showing their site had over 30,000 backlinks and asked why they could not outrank a competitor with 2,000. The answer took about thirty seconds to find. Almost all of those 30,000 links came from four sites: two blog footers, an old partner's sidebar and a scraper site. The competitor's 2,000 links came from more than 400 different websites. Backlinks and referring domains are two very different counts, and confusing them leads to bad decisions.
The definitions
- Backlinks are individual links. Every link from any page anywhere to your site counts once.
- Referring domains are the unique websites those links come from. However many links a site sends you, it counts as one referring domain.
If a Pune tech blog links to your SaaS product from 50 different posts, that is 50 backlinks and 1 referring domain.
Some tools also report referring IPs or referring subnets, which group domains hosted on the same server or network. These can help reveal link networks where many "different" sites share one owner.
Why referring domains usually matter more
Every new site that links to you is a new, independent decision by someone to reference your work, at least in theory. Fifty links from one site reflect one relationship. Google's systems appear to give diminishing value to repeated links from the same domain, which matches common sense: the fiftieth link from the same blog is not fifty times as convincing as the first.
That is why most SEOs set targets in referring domains rather than backlinks, and why competitive analysis is more reliable when you compare referring domain counts.
When the backlink count is still useful
The raw backlink number is not useless. It tells you a few things:
- Sitewide links. A huge backlinks-to-domains ratio usually means a sitewide link in a footer, sidebar or blogroll. These are worth reviewing. A sitewide link from a genuine partner is fine; one from an unrelated site you paid for is a pattern Google has warned about.
- Spam attacks. A sudden jump of thousands of backlinks from a handful of junk domains is a common sign of scraper sites or a negative SEO attempt.
- Content popularity within a site. If one industry blog links to you from many of its posts, they clearly see you as a regular reference, which is a good relationship to nurture.
Reading the ratio
Divide backlinks by referring domains to get a rough average of links per site.
| Situation | What it often means |
|---|---|
| Ratio close to 1–5 | Mostly one-off editorial or contextual links. Typical of healthy profiles. |
| Ratio in the dozens or hundreds | One or more sitewide links, or a few sites linking from many pages. Check which domains. |
| Ratio in the thousands | Almost certainly sitewide or scraper links skewing the numbers. Look at referring domains only. |
These are rules of thumb, not thresholds. A large news site that writes about you every week will naturally create many backlinks from one domain.
Quality still beats quantity
Counting referring domains is better than counting backlinks, but it is still only a count. Two hundred referring domains made up of expired-domain blogs and auto-generated directories will not compete with forty from real, relevant businesses. When you review domains, look at relevance, whether the site has real traffic, and how the link is placed. Our guide to good vs bad backlinks walks through the checks.
Tool numbers differ, and that's normal
Ahrefs, Semrush, Moz and Google Search Console will each show you a different number of referring domains for the same site. They crawl different parts of the web at different speeds and drop lost links at different times. Pick one tool for tracking trends over time and stick with it. Comparing Ahrefs' count for your site with Semrush's count for a competitor gives you noise, not insight.
How to use referring domains in planning
- Find the referring domain counts for the top five pages ranking for your target keyword (use one tool for all of them).
- Note the median, not the highest. One outlier with a huge profile can distort your target.
- Check the gap between that median and your page.
- Plan to close the gap gradually with new domains rather than more links from sites already linking to you.
If you are building links in volume, keep the pace steady. A profile that gains a few new domains every week looks very different from one that gains hundreds overnight, which is covered in backlink velocity. And because domains disappear over time, expect some losses; see lost backlinks and link rot.
Before you move on
Open your backlink tool, sort your referring domains by number of links, and look at the top ten. Any domain sending you hundreds of links from an unrelated site deserves a closer look, and any relevant site sending just one link is a candidate for a stronger relationship.