Every analysis on this site shows the same set of numbers. None of them comes from Google. Each is calculated by an SEO tool company from its own index of the web, or, in the case of domain age, read from a public registry. Knowing what each one measures is the difference between using them well and being sold to with them.
One rule covers all of them: a metric is a clue, not a verdict. They are most useful together and against each other. A site with strong link metrics and no search traffic tells a very different story from one where both are strong.
Domain Authority (DA)
Who: Moz. Scale: 1–100.
Moz describes Domain Authority as a score that predicts how likely a domain is to rank in search results, based mainly on its link data. It is relative and logarithmic in practice: moving from 20 to 30 is far easier than from 70 to 80.
What it is good for: comparing sites in the same niche quickly. What it isn’t: a Google metric. Moz states plainly that Domain Authority is not a Google ranking factor, and Google’s John Mueller has said Google doesn’t use Domain Authority “at all” in crawling, indexing or ranking.
When Moz has no record of a domain, our pages show “1 (Confirm Manually)”: the 1 is a placeholder, not a measurement, so check the domain in Moz directly.
Domain Rating (DR)
Who: Ahrefs. Scale: 0–100.
Ahrefs defines Domain Rating as the strength of a website’s backlink profile compared with the others in its database. Like DA it is relative and logarithmic. Ahrefs’ own explanation adds that DR counts only followed links and only the first link from each referring domain, and that it is purely link-based. Traffic and content quality do not enter it.
Ahrefs itself says there is no evidence search engines use DR as a ranking factor. DA and DR often disagree because Moz and Ahrefs crawl different parts of the web. A gap of 25 points or more is worth investigating, and our analyses flag it.
Spam Score
Who: Moz. Scale: 1–100%.
Spam Score is the percentage of sites with similar features to the one you’re checking that Moz has found to be penalized or banned by Google. Moz bands it as low (1–30%), medium (31–60%) and high (61–100%).
It is a correlation model, not an accusation, and Moz says so itself. Even very large, trusted sites can show a score in the 20s. Treat medium and high scores as a reason to look closer at the site’s outbound links and content, not as proof of anything. When Moz has no Spam Score for a site, we show N/A.
Referring domains
Who: Moz (on our pages).
The number of distinct websites that link to the domain. It is usually more telling than the raw backlink count, because one site can link thousands of times from a sidebar or footer. Many referring domains is a sign that many independent sites chose to link, though it says nothing about whether those sites are any good.
Our detail tables also show two related Moz figures where available: referring domains that link with nofollow, and referring domains whose links Moz has seen removed.
Backlinks
Who: Moz and Semrush.
The total number of links pointing to a domain. Large numbers often come from sitewide links (navigation, footers, blogrolls), so backlinks alone are a weak signal. Compare them with referring domains: millions of backlinks from a few hundred domains points to sitewide or automated links.
Organic traffic and keywords
Who: Semrush. Unit: estimated visits per month.
Semrush estimates how many visitors a domain receives from unpaid search results each month. The estimate, shown in Semrush’s Domain Overview report, comes from the keywords the domain ranks for, their search volume and the typical click-through rate at that position. It is not the site’s analytics. The keywords figure is how many keywords Semrush sees the domain ranking for.
This is the most important number for a link buyer. It is the clearest public sign that Google sends people to the site, and a link on a page people actually find can send visitors too. Two cautions apply:
- It measures search traffic only. A site whose visitors mostly arrive directly or from social media will look smaller than it is.
- No figure is not the same as zero. When Semrush returns nothing, we show N/A and flag it rather than assuming no traffic.
Domain age
Who: the domain’s registry.
The date the domain name was first registered. It is a fact, but a narrow one. It doesn’t show who has owned or run the site since, or whether an expired domain was bought and repurposed. Google’s spam policies specifically cover buying expired domains to exploit their history. So we never score a site higher for being old. Check archived snapshots of the site to see whether its owner or topic changed.
Some registries don’t publish a registration date at all. Our pages then say “not published”.
Page backlinks (PBL)
Who: Semrush.
The number of backlinks Semrush counts to one exact URL. On our pages it is measured for the site’s homepage. This matters more than it sounds, because a guest post or link insertion lives on an inner page, not the homepage. The page your link sits on has its own backlinks, and a brand-new guest post has none at first. The domain’s numbers describe the whole site; your link gets the page’s.
Reading the metrics together
The patterns matter more than any single number:
| Pattern | What it often means |
|---|---|
| Strong DA/DR and strong traffic | A site Google trusts and sends visitors to. A link can be worth having if it is relevant. |
| Strong DA/DR, little or no traffic | Common on sites built to sell links. Investigate before paying. |
| Modest DA/DR, healthy traffic in your niche | Often underpriced: real readers, relevant audience. |
| DA and DR far apart | The tools see different link profiles. Look at the actual referring domains. |
| High Spam Score | Moz associates the site’s features with penalized sites. Review outbound links and content by hand. |
What Google says about these metrics
Google has repeatedly said it does not use Moz’s Domain Authority. Ahrefs says there is no evidence search engines use DR. That doesn’t make the metrics useless. They are reasonable, comparable estimates of link strength and visibility, made by companies that crawl the web at scale. It does mean that no metric on this page proves a link will help you rank. Relevance, the page your link sits on, and whether the link is editorial (the point Google’s spam policies turn on) all matter more, and our analyses weigh those alongside the numbers.
Questions about this guide
What is a good Domain Authority for a backlink?
There is no universal cut-off. DA is relative, so compare a site with others in its own niche instead of against a fixed number, and check that its organic traffic and the page your link would sit on back the score up.
Why are a website’s DA and DR so different?
Moz and Ahrefs crawl different parts of the web and weigh links differently, so each sees a different link profile. A wide gap is a prompt to look at the referring domains themselves, not to trust whichever score is higher.
Does a Spam Score of 1% mean a site is safe?
No. Spam Score estimates risk from traits a site shares with penalized ones, so a low figure says those traits are rare, not that the site is clean. Its outbound links and recent posts are the real test.