Spam Score
Spam Score is a Moz metric from 1% to 100% that estimates how likely a site is to be penalized by Google, based on features it shares with penalized sites. Higher means riskier.
Calculation Approach
Spam Score comes from Moz, the company behind Domain Authority and Page Authority. It is shown in Moz’s Link Explorer and toolbar, and it estimates the risk that a domain or subdomain is spammy.
Moz built the score by studying sites that Google had penalized or banned. Its research team looked for features those sites had in common and identified 27 signals that appeared far more often on penalized sites than on healthy ones. Each site Moz crawls is checked against those features.
The signals cover several areas. Some relate to the domain itself, such as unusual domain name length or numerals in the name. Some look at content, such as very thin pages or very few pages overall. Others look at links, such as a small share of branded anchors or an unusual mix of followed and nofollow links. Missing contact information and other site details can count too.
Moz then uses machine learning to turn those signals into a percentage. The score reflects how many penalized sites with a similar set of features Moz found in its research. A Spam Score of 40% means that, among sites Moz studied with similar features, around 40% had been penalized or banned by Google.
That point matters. Spam Score does not say a site is spammy. It says the site shares traits with sites that were. A legitimate small business with a thin website and few links can show a higher score without doing anything wrong.
Moz groups scores into three bands. Scores from 1% to 30% are considered low risk, 31% to 60% medium risk and 61% to 100% high risk.
Interpreting Spam Score
Spam Score is most useful for judging other sites, especially sites that link to you or sites you might get links from.
When checking link prospects, a low Spam Score is a reasonable sign that a site is not part of an obvious spam network. A high score is a prompt to look closer. Visit the site, read the content, check its traffic and look at who else it links to. Many link builders use Spam Score as a first filter before manual review, alongside metrics such as Semrush’s Authority Score.
In backlink audits, Spam Score helps sort your referring domains. Sorting by score brings potentially risky sites to the top of the list. Domains with high scores and other warning signs, such as irrelevant content, foreign-language spam or link-selling pages, deserve attention first.
For your own site, a high Spam Score is less worrying than it sounds. Google does not use the metric. If your site is new, small or lacks branded links, the score may be higher for reasons that will fade as the site grows. Focus on the specific features Moz flags rather than the number itself.
Context matters in every case. A site with Spam Score 35% and real traffic, useful content and relevant links is often a fine link source. A site with Spam Score 10% that publishes paid posts for anyone can still be risky. Spam Score is one signal, not a verdict.
Limitations of Spam Score
Spam Score has clear limits.
Google does not use it. It is a third-party estimate, not a measure of how Google sees a site. Google has its own systems, including SpamBrain, which work very differently.
It is based on correlation. The score reflects features that penalized sites tend to share. Plenty of legitimate sites share some of those features, and some spammy sites avoid them.
It can flag the wrong sites. Small businesses, new blogs, niche hobby sites and sites in certain countries can show higher scores without being spammy.
It can miss real spam. Link sellers with polished sites, healthy-looking link profiles and real traffic may score low while still selling links openly.
It depends on Moz’s index. If Moz has not crawled a site fully, its signals may be incomplete.
It does not judge relevance or quality. A site can have a low score and still be a poor fit for your niche or your link goals.
It changes over time. Moz updates its index and models, which can move scores without any change on the site.
For these reasons, treat Spam Score as a starting point for review. It is good at pointing out sites that need a closer look, and weak as a final judgment.
Response Actions
What to do with a Spam Score depends on whose site it is.
For sites linking to you, review high-scoring domains manually. If a domain is clearly spammy, irrelevant and part of a manipulative pattern, consider asking for removal. If that fails and the links form a real risk, a disavow file is a last resort. Remember that Google ignores most low-quality links automatically. A guide to spammy links helps separate genuine threats from ordinary noise.
For link prospects, use the score as a filter, then check the site by hand. Look at traffic, content quality, outbound links and whether the site sells placements. Skip sites that fail those checks, whatever their score.
For your own site, look at the features behind the score. Common fixes include adding clear contact details and an about page, publishing more useful content, earning branded links and cleaning up any low-quality links from past campaigns.
Keep a record of your reviews. Note which domains you checked, what you found and what action you took. This helps with future audits and with any reconsideration request if a manual action ever occurs. A full SEO audit service usually includes this kind of backlink review alongside technical and content checks.
Do not panic over a single number. A rising Spam Score is a reason to investigate, not proof of a problem.
Spam Score estimates how closely a site resembles sites Google has penalized. Use it to flag domains for manual review, pair it with traffic, relevance and content checks and treat it as one signal rather than a verdict on any site.