One number counts links, the other counts websites
Every link tool gives you two headline figures. Backlinks is the count of individual links pointing at your site. Referring domains is the count of distinct websites those links come from. The second number is smaller, slower to move, and much harder to fake.
The gap between them is where link reports go to hide. A single WordPress theme that drops your link into the footer of a 4,000-page site produces 4,000 backlinks and one referring domain. Search engines work that out immediately — sitewide template links have been consolidated for years, and the ten-thousandth copy of the same link is worth nothing extra. Your monthly report frequently doesn't make the same adjustment.
| Backlinks | Referring domains | Ratio | What it usually is |
|---|---|---|---|
| 4,120 | 12 | 343:1 | A sitewide footer or blogroll link. One relationship, repeated on every page. |
| 380 | 210 | 1.8:1 | Ordinary editorial linking. Most sites link once, a few link twice. |
| 1,900 | 60 | 32:1 | A handful of large sites linking repeatedly — sometimes genuine syndication, sometimes a paid network. |
The ratio check, in about a minute
You don't need a paid tool to do this, and you don't need to be technical. You need two numbers and a calculator.
- Open your link tool of choice, or the free Links report in Google Search Console, and note two figures: total backlinks and total referring domains.
- Divide backlinks by referring domains. That's your ratio.
- Under roughly 5:1, stop worrying. Sites naturally accumulate a few links from the same domain — an author page, a category archive, a second article that references the first.
- Above roughly 10:1, sort your backlinks by linking domain and look at the largest one. If a single site accounts for more than a quarter of your total links, you've found your explanation.
- Check where those links sit on the page. Footer, sidebar and blogroll placements are template links. They're not fraud, they're just one vote wearing a thousand costumes.
Where the inflated ratios come from
Not every high ratio is a scam. Most of them are ordinary web plumbing that a report chose not to explain.
- Footer credits. "Website by X" on every page of a client's site. Entirely legitimate, and worth exactly one referring domain.
- Blogroll and partner sidebars. Same mechanic, usually a worse neighbourhood.
- Syndicated content. One article republished across a group's network of titles. Real coverage, one publisher.
- Widgets and badges. Award badges, "as featured in" strips, embedded calculators. Google has been warning about keyword-stuffed widget links for over a decade.
- Paid networks. The version sold by the thousand, usually on the same few hosting ranges. See paid links vs earned links for what happens when the network gets deindexed and your profile deflates overnight.
Growth, and the only competitor comparison worth making
A referring domain total tells you nothing on its own. The rate of change tells you almost everything. Pull the number on the first of every month and keep the list of new domains beside it.
What counts as a good pace depends entirely on your category and your budget — a fintech blog publishing data nobody else has will outpace a plumbing company by an order of magnitude, and neither is doing anything wrong. What's diagnosable is the shape. Steady single- or double-digit gains, month after month, look like work. A flat line for two months followed by 400 domains in one week looks like a purchase.
Then the comparison. Don't benchmark against the largest brand in your market — benchmark against the three or four sites that actually outrank you for the keywords you care about. Pull each one's referring domain count, then look at the overlap: domains linking to all three of them and none to you. That list is the honest brief for a link building programme, and it's a great deal more useful than a target number.