A domain spam score is one of the most misunderstood metrics in expired domain research. Many domain buyers treat it as a penalty verdict: if the score is high, they assume the domain is ruined. If it's low, they think they're safe. Neither is quite true. The spam score is a correlation tool, not a Google ranking signal, and it can mislead you in both directions.
This guide explains what the metric actually measures, why it misleads, and what checks you should run instead when deciding whether a domain's history is clean enough to buy.
What spam score is and who computes it
Moz, the SEO tools company, publishes a metric called Spam Score. It is the percentage of sites with similar features that Moz found to be penalised or banned. Moz does not compute this score from Google data.
This is why it is a correlation, not a verdict: a high score means a domain looks similar to sites that were penalised or banned. It does not mean Google has penalised this domain.
What it measures: similarity to penalized sites
The Spam Score compares a site with sites that Moz found to be penalised or banned, and reports the share that were. The exact features and weights are Moz's own, so check Moz's documentation for the current details.
This is useful information, but it is not a substitute for reading your domain's actual link profile. A site can have a low spam score and still carry links from private blog networks (PBNs). Conversely, a niche site with many links from other sites in the same small community might score high on spam indicators even though those links are genuine and helpful.
Good and bad ranges
There is no official threshold that counts as "safe," and different SEO practitioners use different rules of thumb. A higher score is a reason to look at the link profile in detail, and a very high score deserves a hard look before you bid. These are community habits, not Moz guidance. A domain with a high score is not automatically unusable, and a domain with a low score is not automatically safe.
Why spam score misleads: false positives and false negatives
The spam score has two consistent failure modes.
False positives: A domain can score high and be completely safe. This can happen when a small, genuine site shares some features with sites that Moz found to be penalised. The score rises even though the domain has no actual penalty risk, and reading the real link profile shows it.
False negatives: A domain can score low and still carry major risk. Private blog networks (PBNs) have evolved to avoid obvious spam signals. If a network of sites is carefully designed to avoid detection, each site might look legitimate enough to score low on spam indicators. A domain could have a spam score of 12% and still be linked from hidden PBN networks.
The spam score also does not catch Google manual actions. If Google's spam team has reviewed a domain and applied a manual action, the spam score gives you no warning. The domain looks clean by every automated metric, but Google has flagged it behind the scenes.
The real checks when spam score is high
If you find an expired domain with a high spam score, do not assume it is unusable. Instead, run these checks:
1. Read the backlink profile. Open the domain in Ahrefs or Semrush and look at the list of linking domains. Are they from established sites in the same industry, or do they look like low-quality link farms? Can you click through and see real content, or do they look auto-generated?
2. Check the anchor text. Do the links use relevant, natural anchor text like "dog training tips," or do they all use exact-match keywords like "best dog trainer" repeated identically across many domains? Natural variation suggests real links; repetition suggests artificial linking.
3. Review the archive history. Look at the Wayback Machine to see what the site actually published. A legitimate site with a high spam score is easy to verify: you see real, coherent content across years. A spam site shows signs of change, keyword insertion, or auto-generated pages.
4. Run a blacklist check. Use the domain reputation check to see if the domain appears on Spamhaus DBL or SURBL, or if Google Safe Browsing flags it. These are stronger indicators of actual abuse than a Spam Score.
5. Check for a Google manual action. Manual actions are visible only to the verified owner in Search Console. You cannot see this before you own the domain, but once you do, you can check the Manual Actions report.
Can you lower a spam score?
If you buy a domain with a high spam score, you cannot set it directly. Moz calculates the score itself, and how often it updates is Moz's decision.
What you can do:
- Build new, high-quality backlinks pointing to your new content
- Disavow the worst links if you want to ask Google to ignore them
- Publish genuinely useful content that earns links from better sites
Over time, the score may change as the site and its links change, but there is no guarantee and no fixed timeline. A better strategy is to avoid the domain in the first place if the high score reflects real link network problems, or to accept the score if your research shows the links are actually safe.
The spam score's place in choosing an expired domain
Use the spam score as a screening tool, not a verdict. If it is very high without a clear reason, that is a warning sign worth investigating. If it is moderate, run the checks above. If it is very low, do not assume the domain is safe; you still need to check the archive history and look at the broader domain profile.
At hunter.domains, we do not rely on a single metric. Domains go through link-network detection and the Spamhaus DBL and SURBL blacklists, and the risk flags are shown rather than hidden, such as trademark risk, an archive gap or a topic change. Together, these signals give you a clearer picture than any single metric alone.
Remember: the spam score is a hint, not a diagnosis. Your job as a buyer is to follow the hints to the real evidence. See how the scanning, filtering and scoring works for the signals we use in place of a single score.
Frequently asked questions
What is a good spam score?
A good spam score depends on how much risk you want to take. Lower is generally better, but a moderate score can still be safe if your research shows the links are legitimate, and a low score does not prove a domain is clean. A high score warrants a detailed investigation of the link profile and the archive.
How to check spam score of a website?
Spam Score is a Moz metric, so look the domain up in Moz's own tools. Check Moz's site for what is currently free and what needs an account. Ahrefs and Semrush have their own metrics and do not report Moz's score.
Does Google use spam score?
No. Google does not use Moz's Spam Score as a ranking factor. Moz's score is a correlation based on Moz's research, not a metric Google publishes or directly acts on. Google has its own proprietary systems for detecting spam, but those are not visible to the public. The spam score is useful as a research tool, but it is not a Google signal.
