A domain comes back with a Moz Spam Score of 45%, and the first instinct is to drop it from the shortlist or start drafting a disavow file. Most of the time neither is needed. Spam Score is a useful screening signal, but it measures something narrower than its name suggests. Read as a prompt to look closer, it saves time. Read as a verdict, it pushes you toward bad calls on link prospects, guest-post sites and expired domains alike.
Here is how I read the number, based on what Moz itself says about it.
What Moz Spam Score actually measures
According to Moz's Help Hub, Spam Score represents the percentage of sites with similar features to the site you're researching that Moz has found to be penalized or banned by Google. The score comes from a machine learning model trained on known penalized and banned domains, and that model identified 27 features common among them.
So a score of 40% does not mean a site is "40% spam." It means that among sites sharing a similar combination of features, about 40% were penalized or banned in Moz's data. It describes the group a site resembles, not the site's own record.
Moz is direct about this. Its documentation says the score is based on correlation with penalization rather than causation, and that a high score is a sign to investigate quality and relevance further, not proof that a site is spammy. Spam Score is also a third-party metric. It is Moz's estimate, not a Google score, and there is no Spam Score threshold that triggers a Google penalty.
A few details from Moz's FAQ are easy to miss:
The score is calculated for the site itself. It is not an average of the sites linking to it.
A score shown as "--" means Moz has not evaluated that site yet. That is missing data, not a clean result.
Spam Score updates quarterly, and an individual site's score changes only when Moz's crawlers detect changes in the signals behind it. Moz does not show historical scores.
What the Moz Spam Score ranges mean
Moz groups scores into three bands:
1–30%: Low Spam Score
31–60%: Medium Spam Score
61–100%: High Spam Score
For your own site, Moz says that if you have not had any penalties, a Low or Medium score is not something to worry about. For other sites, the bands work best as triage queues:
Low: continue with your normal quality checks. A low score is not an endorsement.
Medium: look at the content and the link profile before you commit time or money.
High: review manually before any decision. Some of these sites will turn out fine, and some will confirm the warning.
Why a high score isn't automatically a penalty
The quickest way to calm down about a high score is to read the list of signals. Moz publishes all 27. Among them:
a low number of pages found on the domain;
numerals, many hyphens or unusual vowel and consonant runs in the domain name;
a top-level domain that correlates with spam;
no phone number, email address or LinkedIn link;
not defaulting to HTTPS, and no favicon;
no Google Tag Manager, Google Font API, Doubleclick or Facebook Pixel;
very short or very long title and meta description tags;
abnormally high or low numbers of external links and linked domains;
"poison words" in content and high-CPC anchor text in outbound links.
Many of these describe a small or plain site rather than a bad one. A new niche blog with a dozen pages, no tag manager and no contact page can trip several at once without having done anything wrong. A parked or dropped domain trips even more, simply because there is almost nothing on it to crawl.
Moz adds two caveats that matter in practice. The numbering of the signals says nothing about their weight, and Moz does not currently show which of the 27 a particular site triggered. You have to look at the site and work it out yourself.
The last two signals deserve more attention than the rest. Poison words and high-CPC anchors point at the topics that attract real link spam: pharmaceuticals, adult content, gambling. If a high score seems to come from those, take it seriously. If it seems to come from a thin site with no tracking scripts, it is far less alarming.
How to check Spam Score signals in context
The same number can describe very different sites. Spam Score becomes useful once you read it next to other data.
Start with authority and referring domains
A 35% score on a site with solid Domain Authority and hundreds of referring domains is a different case from 35% on a thin site with almost no links. That is why our spam score checker shows Moz Spam Score next to Domain Authority, backlinks and referring root domains from the same Moz lookup, for a short list of domains side by side. Comparing a shortlist this way makes it obvious which high scores come with a real link profile and which come from near-empty hosts.
Look at the link profile, not only the number
In Moz Link Explorer, the Spam Score breakdown shows what share of a site's linking domains falls into each band, with inbound links sorted by Spam Score. Open the highest-scoring linking pages and ask:
Do the links come from relevant sites, or from scraper pages and directories with no visible audience?
Do the anchors look natural (brand name, URL, descriptive phrases), or are commercial exact-match keywords repeated across many domains?
Is there a sudden cluster of links from unrelated languages or topics?
Moz recommends exactly this: check a site's content and its relevance to you before disregarding it or disavowing links from it.
Expired domains need extra care
With expired and dropped domains, the score reflects the domain as Moz last crawled it. That may be a parking page, an empty host, or a site a previous owner repurposed. A dropped domain with a thin parking page can score higher than the same name did when it was an active site. The reverse also happens: a domain that was hacked or turned into a gambling doorway can carry a moderate score that hides its history.
When you screen a large pool of expired domains, Spam Score is a fast way to sort candidates into queues. The final call still depends on history. For each domain on your shortlist:
review archived snapshots across several years to see what the site actually was;
note abrupt changes in topic or language;
scan anchor text for pharma, gambling and adult terms;
compare today's link profile with what the old site would plausibly have earned.
When to act on your own site's score
If your own domain shows a Medium or High score, remember Moz's own caveat: because the score reflects correlation, the fix isn't necessarily to change those factors.
Disavowing is a bigger step. Google's Search Console documentation says that in most cases Google can assess which links to trust on its own, so most sites will not need the disavow tool. Google recommends disavowing only when you have a considerable number of spammy, artificial or low-quality links and those links have caused a manual action, or likely will. It also warns that incorrect use can harm a site's performance in search. A high Spam Score on some linking domains, by itself, meets neither condition.
A practical Spam Score checklist
Confirm the score exists. "--" means Moz has not evaluated the site.
Note the band: Low, Medium or High.
Read the score next to Domain Authority, backlinks and referring domains.
Look at the site and estimate which signals it likely triggers: page count, contact details, HTTPS, title lengths, outbound links.
Separate "small site" signals from "spam topic" signals such as poison words and high-CPC anchors.
Review the highest-scoring linking domains and their anchor text.
For expired domains, check archived history and any change in topic or language.
For your own site, check the Manual actions report in Google Search Console before you consider a disavow file.
Write down the decision and recheck later, since Moz refreshes Spam Score quarterly.
Spam Score FAQ
What is a good Moz Spam Score?
Moz classifies 1–30% as Low. There is no universal "good" number, though. A low score on a site with almost no links tells you little, so always read it next to authority and link data.
How do I check Moz Spam Score?
Moz shows Spam Score in Link Explorer and in the Links section of a Moz Pro Campaign. For many domains at once, Moz offers the Links API or a CSV export from a Link Tracking List.
Does Google use Moz Spam Score?
No. Spam Score is Moz's own metric. Moz trained its model on sites that Google penalized or banned, but the result is Moz's estimate, not a Google ranking factor or a penalty threshold.
Can I see which signals my site triggers?
Not in Moz at the moment. Moz says this breakdown isn't currently available and suggests reviewing your site against the published list of 27 signals.
Can I lower my Moz Spam Score?
Only by changing the signals Moz detects, and the score moves only on a quarterly update. Since the signals are correlations, chasing them (adding a tag manager or a favicon) rarely matters unless you have an actual penalty.
Do linking domains with high Spam Scores hurt my site?
Not automatically. Google says it can usually work out which links to trust, and it reserves the disavow tool for cases involving a considerable number of bad links tied to a manual action, actual or likely.
How often does Spam Score change?
Moz updates it quarterly. A site's score only moves when Moz detects changes in the underlying signals, and there is no history view.
The short version: treat Spam Score as a reason to look, not a reason to act. Read it with authority and link data, figure out which signals are behind it, and save disavows and rejections for the cases where the evidence goes beyond one number.
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