A Complete Guide to Understanding Moz’s Spam Score

Editor’s Note: This post was originally published in April 2024 and has been comprehensively updated in December 2025.

Spam Score is one of the most misunderstood metrics in SEO. This comprehensive guide explains what Spam Score really means, how to interpret it correctly, and how to use it strategically to protect your website’s search rankings and build a high-quality backlink profile.

In the complex world of SEO, understanding which metrics truly matter can feel overwhelming. With countless tools, scores, and rankings to monitor, it’s easy to become paralysed by data or, worse, focus on the wrong signals entirely.

One metric that frequently causes confusion—and sometimes unnecessary panic—is Spam Score. Developed by Moz, one of the most respected names in SEO software, Spam Score offers valuable insights into domain quality and potential risks. However, many bloggers and website owners misinterpret what this metric actually means, leading to poor decisions about link building and site management.

In this comprehensive guide, I’ll demystify Spam Score, explain exactly what it measures (and what it doesn’t), show you how to interpret different score ranges, and provide practical strategies for using this metric to strengthen your SEO efforts and protect your site’s reputation.

What is Spam Score?

Spam Score is a proprietary metric developed by Moz and available exclusively within their Link Explorer tool. It’s designed to help SEO professionals and website owners assess the potential risk associated with linking to or receiving links from specific domains.

How Spam Score Works

Moz’s Spam Score uses a sophisticated machine learning model that analyses millions of websites that have been penalised or banned by Google. By studying these penalised sites, Moz identified 27 common features—or “spam flags”—that frequently appear across low-quality, spammy domains.

The 27 spam flags include characteristics such as:

Thin content with little substantive value
Excessive external links on pages
Low number of internal links
High ratio of external to internal links
Small site structure (very few pages)
Large site structure with shallow content
Low Domain Authority
High percentage of branded anchor text
Low percentage of branded anchor text
Unusually high or low percentage of exact match anchor text
Toxic anchor text patterns
Suspicious TLD (top-level domain)
Domain name length (very short or very long)
Presence of numbers in domain name
Double extensions in domain name
Low number of pages found in Google’s index
High proportion of links from low-authority sites
Suspicious link velocity patterns

When Moz’s algorithm scans a domain, it checks how many of these 27 flags are present. The more flags a site triggers, the higher its Spam Score.

What Spam Score Measures (and What It Doesn’t)

Here’s the crucial distinction: Spam Score measures correlation, not causation.

This means that while penalised sites frequently share these 27 characteristics, having these characteristics doesn’t automatically mean a site is spammy or will be penalised. It simply means the site shares features commonly found on penalised domains.

Think of it like this: If you studied 1,000 houses that burned down and found that 80% had faulty wiring, you could create a “Fire Risk Score” based on wiring characteristics. A house with similar wiring patterns would score high on your Fire Risk Score—but that doesn’t guarantee the house will burn down. It simply means it shares characteristics with houses that did.

Similarly, a high Spam Score indicates that a domain shares characteristics with penalised sites, but it doesn’t definitively prove the site is spam or will be penalised.

Why Spam Score Matters for Bloggers

Despite its limitations, Spam Score serves several valuable purposes:

Risk assessment for link building: Before placing a guest post or securing a backlink, checking the Spam Score helps you avoid associating your site with potentially toxic domains.

Backlink profile auditing: When reviewing your existing backlinks, Spam Score helps you identify potentially problematic links that might warrant removal or disavowal.

Competitive analysis: Understanding competitors’ Spam Scores can reveal opportunities or risks in your niche’s link landscape.

Due diligence for partnerships: Before entering into content partnerships, sponsored post arrangements, or link exchanges, Spam Score provides an additional data point for vetting potential partners.

Early warning system: A sudden increase in your own Spam Score can alert you to potential issues with your site structure, content quality, or link profile before they escalate into penalties.

Understanding Spam Score Ranges

Moz categorises Spam Score into three primary ranges, each indicating different levels of potential risk. Understanding these ranges—and what they mean in practical terms—is essential for making informed SEO decisions.

Low Spam Score (0-30%)

What it means: The domain triggers between 0 and 8 of the 27 spam flags.

Risk level: Low to minimal risk.

Interpretation: Sites in this range share few characteristics with penalised domains. They typically have:

Reasonable content quality and quantity
Natural link profiles with diverse anchor text
Established domain authority
Proper site structure and internal linking
Legitimate business presence or purpose

Action required: Generally, no action is needed. Sites with low Spam Scores are typically safe to link to or receive links from, assuming other quality indicators (content relevance, topical authority, user experience) are also positive.

Important caveat: A low Spam Score doesn’t guarantee a site is high-quality or relevant to your niche. Always evaluate content quality, topical relevance, and audience alignment independently.

Medium Spam Score (31-60%)

What it means: The domain triggers between 9 and 16 of the 27 spam flags.

Risk level: Moderate risk; requires further investigation.

Interpretation: Sites in this range share a moderate number of characteristics with penalised domains. This doesn’t automatically mean they’re spammy, but it warrants closer examination.

Common reasons for medium Spam Scores:

New websites with limited content and backlink history
Sites undergoing major restructuring or rebranding
Niche sites with naturally limited content scope
Sites with aggressive but not necessarily black-hat SEO tactics
Legitimate sites with some technical SEO issues
Sites in industries with naturally higher spam prevalence (gambling, pharmaceuticals, adult content)

Action required: Conduct a manual review before making linking decisions:

Content quality: Is the content substantive, original, and valuable?
Site purpose: Does the site serve a legitimate purpose for real users?
User experience: Is the site professionally designed and easy to navigate?
Advertising: Are ads reasonable, or does the site feel like an ad farm?
Domain history: Has the domain changed hands or niches recently?
Traffic patterns: Does the site receive genuine organic traffic?

If the site passes these manual checks despite the medium Spam Score, it may be acceptable for linking purposes—but proceed with caution and continue monitoring.

High Spam Score (61-100%)

What it means: The domain triggers between 17 and 27 of the 27 spam flags.

Risk level: High risk; strong caution advised.

Interpretation: Sites in this range share a significant number of characteristics with penalised domains. While not all high-Spam-Score sites are definitively spam, the risk is substantial.

Common characteristics of high-Spam-Score sites:

Thin, low-quality, or duplicate content
Excessive outbound links to unrelated sites
Suspicious link profiles with unnatural anchor text patterns
Recent domain purchases with complete content/niche changes
Private blog networks (PBNs)
Link farms or link exchange schemes
Sites created primarily for SEO manipulation rather than user value
Abandoned or hacked sites with injected spam content

Action required: Exercise extreme caution:

For inbound links (links pointing to your site): Consider disavowing links from high-Spam-Score domains, especially if you’ve experienced ranking drops or received manual action warnings from Google.

For outbound links (links from your site): Avoid linking to high-Spam-Score sites unless you have compelling evidence that the site is legitimate and the Spam Score is a false positive. Even then, use “nofollow” attributes to protect your site.

For guest posting or content partnerships: Generally avoid placing content on high-Spam-Score sites, as the association could harm your site’s reputation and rankings.

Important exception: Occasionally, legitimate sites receive high Spam Scores due to technical issues, recent migrations, or false positives. If you have a strong reason to believe a high-Spam-Score site is legitimate, conduct an extremely thorough manual review and consider reaching out to the site owner to understand the score’s cause.

How to Check Spam Score

To access Spam Score data, you’ll need a Moz account with access to Link Explorer. Here’s how to check Spam Score for any domain:

Step 1: Access Moz Link Explorer

Navigate to Moz.com and log into your account
Click on “Link Explorer” in the main navigation menu
If you don’t have a Moz account, you can sign up for a free trial or choose a paid plan (starting at approximately £79/month for Moz Pro)

Step 2: Enter the Domain

In the search bar, enter the full domain you want to check (e.g., “example.com”)
Do not include “http://” or “https://” or specific page URLs—just the root domain
Click “Search” or press Enter

Step 3: Review the Spam Score

The Spam Score will be displayed prominently in the domain overview section
It’s shown as a percentage (e.g., “15% Spam Score”)
Click on the Spam Score percentage to see which specific spam flags the domain triggers

Step 4: Analyse the Spam Flags

Understanding which specific flags a domain triggers is often more valuable than the overall score:

Review the list of triggered flags
Consider whether these flags represent genuine quality issues or false positives
Use this information to make more nuanced decisions about the domain

Checking Your Own Site’s Spam Score

Regularly monitoring your own Spam Score is good practice:

Check your Spam Score monthly or quarterly
Track changes over time to identify potential issues early
If your Spam Score increases significantly, investigate recent changes to your site structure, content, or link profile
Address any legitimate issues highlighted by the spam flags

Practical Applications of Spam Score

Understanding Spam Score is one thing; using it strategically to improve your SEO is another. Here are the most valuable practical applications of this metric.

1. Vetting Potential Link Building Opportunities

Before pursuing a backlink from a specific site—whether through guest posting, sponsored content, or organic outreach—check the site’s Spam Score.

Decision framework:

0-30% Spam Score: Proceed with confidence, assuming other quality indicators are positive
31-60% Spam Score: Conduct thorough manual review; proceed only if content quality and relevance are excellent
61-100% Spam Score: Avoid unless you have compelling evidence the site is legitimate; if proceeding, use “nofollow” links

Additional considerations:

Evaluate Domain Authority and Page Authority alongside Spam Score
Check the site’s organic traffic using tools like Ahrefs or SEMrush
Review the site’s content quality and topical relevance
Assess the site’s existing outbound link profile (linking to many low-quality sites is a red flag)

2. Auditing Your Existing Backlink Profile

Regularly reviewing your backlink profile for potentially toxic links is essential for maintaining healthy SEO.

How to conduct a Spam Score backlink audit:

Export your complete backlink profile from Google Search Console, Ahrefs, or SEMrush
Use Moz Link Explorer to check the Spam Score of your top linking domains
Prioritise reviewing links from domains with Spam Scores above 60%
For high-Spam-Score links, determine whether they’re:
- Legitimate links from quality sites with false positive scores
- Low-quality links you should disavow
- Links from private blog networks or link schemes
Create a disavow file for clearly toxic links and submit it through Google Search Console

When to disavow links:

Links from confirmed spam sites or private blog networks
Links with suspicious anchor text patterns (over-optimised exact match)
Links from hacked sites with injected spam content
Links from sites in completely unrelated niches with no editorial justification
Links you didn’t request and that appear manipulative

When NOT to disavow links:

Links from legitimate sites with high Spam Scores due to technical issues
Links from new or small sites with medium Spam Scores
Links with natural anchor text from topically relevant sites
Most links with Spam Scores below 40%

3. Evaluating Content Partnership Opportunities

When brands, agencies, or other bloggers approach you about content partnerships, sponsored posts, or link exchanges, Spam Score provides valuable due diligence.

Red flags to watch for:

High Spam Score combined with recent domain registration (possible PBN)
High Spam Score with frequent niche changes (domain flipping)
Medium to high Spam Score with thin content across the site
Requests to place links to multiple unrelated sites (link insertion schemes)

Green flags:

Low Spam Score with established domain history
Consistent topical focus and content quality
Reasonable organic traffic and engagement metrics
Professional communication and transparent business practices

4. Competitive Analysis

Understanding your competitors’ Spam Scores and backlink profiles can reveal opportunities and risks in your niche.

What to analyse:

Do your top competitors have low Spam Scores and clean link profiles? (This suggests white-hat SEO is effective in your niche)
Are competitors ranking well despite high Spam Scores? (This might indicate Google hasn’t caught up yet, or the niche is less competitive)
Which high-authority, low-Spam-Score sites link to competitors but not to you? (Potential outreach targets)
Are competitors using risky link building tactics? (Opportunity to differentiate with quality)

5. Monitoring Your Own Site’s Health

Your own Spam Score can serve as an early warning system for potential issues.

Establish a baseline:

Check your Spam Score when your site is healthy and ranking well
Document which spam flags your site triggers (if any)
Set a reminder to recheck quarterly

Watch for changes:

Sudden increases in Spam Score may indicate:
- Technical SEO issues (broken internal links, thin content)
- Negative SEO attacks (toxic backlinks pointing to your site)
- Site structure problems after a redesign or migration
- Content quality issues after scaling up production
Investigate and address the root cause promptly

Common Spam Score Myths and Misconceptions

Spam Score is frequently misunderstood, leading to unnecessary anxiety or poor SEO decisions. Let’s debunk the most common myths.

Myth 1: “A High Spam Score Means My Site Will Be Penalised”

Reality: Spam Score measures correlation with penalised sites, not causation. Many legitimate sites have medium or even high Spam Scores due to technical quirks, niche characteristics, or false positives—and they rank perfectly well in Google.

Spam Score is a Moz metric, not a Google metric. Google doesn’t use Spam Score in its algorithms. While the characteristics Spam Score measures may correlate with quality issues Google cares about, the score itself has no direct impact on rankings.

Myth 2: “I Should Only Build Links from Sites with 0% Spam Score”

Reality: This approach is unnecessarily restrictive and will severely limit your link building opportunities. Many excellent, authoritative sites have Spam Scores in the 10-30% range due to minor technical issues or false positives.

Focus on overall quality indicators—content relevance, Domain Authority, organic traffic, user experience—rather than fixating solely on achieving a perfect 0% Spam Score.

Myth 3: “Spam Score Is the Most Important Link Quality Metric”

Reality: Spam Score is one data point among many. Other critical metrics include:

Domain Authority and Page Authority
Topical relevance and content quality
Organic traffic and engagement
Link profile diversity and naturalness
Site age and history
User experience and site speed

Never make linking decisions based solely on Spam Score. Use it as part of a comprehensive quality assessment.

Myth 4: “If a Site Links to Me with a High Spam Score, I Need to Disavow It Immediately”

Reality: Google is quite good at ignoring low-quality links automatically. Unless you’ve received a manual action notification or experienced significant ranking drops, aggressive disavowing is usually unnecessary and can sometimes do more harm than good.

Focus disavow efforts on clearly manipulative links—private blog networks, link farms, hacked sites—rather than every link from a site with a medium-to-high Spam Score.

Myth 5: “New Sites Always Have High Spam Scores”

Reality: While new sites sometimes trigger spam flags due to limited content and backlink history, many new sites have low Spam Scores if they’re built with proper structure, quality content, and natural link acquisition from the start.

Age is just one of 27 factors. A well-built new site can have a lower Spam Score than a poorly maintained older site.

How to Improve Your Site’s Spam Score

If your site has a higher Spam Score than you’d like, here are actionable steps to address the underlying issues.

1. Audit and Improve Content Quality

Thin content is one of the most common spam flags. Review your site for:

Pages with fewer than 300 words (expand or consolidate)
Duplicate content (rewrite or canonicalise)
Low-value pages (consider noindexing or removing)
Content that doesn’t serve user intent (improve or remove)

Action steps:

Identify your lowest-performing pages using Google Analytics
Expand thin content to at least 500-800 words with substantive information
Remove or consolidate pages that don’t add unique value
Ensure every page serves a clear purpose for users

2. Fix Internal Linking Structure

Poor internal linking triggers multiple spam flags. Strengthen your site structure by:

Adding contextual internal links within content
Creating topic clusters with pillar pages and supporting content
Ensuring every page is reachable within 3-4 clicks from the homepage
Fixing broken internal links
Using descriptive anchor text for internal links

Action steps:

Run a site crawl using Screaming Frog or Sitebulb
Identify orphan pages (pages with no internal links)
Create a logical internal linking strategy
Add 3-5 relevant internal links to each piece of content

3. Clean Up Your Backlink Profile

Toxic backlinks can increase your Spam Score. Conduct a thorough backlink audit:

Identify links from high-Spam-Score domains
Look for unnatural anchor text patterns
Find links from irrelevant or suspicious sites
Check for links from known private blog networks

Action steps:

Export your backlink profile from Google Search Console
Use Moz Link Explorer to check Spam Scores of linking domains
Create a disavow file for clearly manipulative links
Submit the disavow file through Google Search Console
Monitor changes over subsequent months

4. Optimise External Link Ratio

Excessive external links relative to internal links can trigger spam flags. Review your outbound linking:

Count external links per page (aim for fewer than 10-15 on most pages)
Ensure external links are relevant and add value
Balance external links with strong internal linking
Use “nofollow” attributes for sponsored or untrusted links

Action steps:

Audit pages with unusually high external link counts
Remove or consolidate unnecessary external links
Strengthen internal linking to improve the ratio
Ensure all external links serve a clear user benefit

5. Address Technical SEO Issues

Several spam flags relate to technical SEO problems:

Low number of indexed pages (improve crawlability and indexation)
Suspicious domain characteristics (if possible, rebrand to a more professional domain)
Poor site structure (reorganise content into logical categories)

Action steps:

Submit an XML sitemap to Google Search Console
Fix crawl errors and broken pages
Improve site speed and mobile responsiveness
Ensure proper use of robots.txt and meta robots tags

6. Build High-Quality, Diverse Backlinks

Lack of authoritative backlinks can contribute to higher Spam Scores. Focus on earning quality links:

Create linkable assets (original research, comprehensive guides, tools)
Pursue guest posting on authoritative, low-Spam-Score sites
Build relationships with influencers and journalists in your niche
Earn editorial links through exceptional content

Action steps:

Identify link building opportunities using Ahrefs or SEMrush
Create content specifically designed to attract backlinks
Conduct strategic outreach to relevant sites
Monitor new backlinks and their quality metrics

Strategic Considerations for Using Spam Score

To maximise the value of Spam Score in your SEO strategy, keep these strategic principles in mind.

Balance Spam Score with Other Metrics

Never rely solely on Spam Score. Always evaluate:

Domain Authority (DA): Higher DA generally indicates more established authority
Content quality: Read actual content to assess value and relevance
Topical relevance: Links from topically related sites are more valuable
Traffic metrics: Check organic traffic using Ahrefs or SEMrush
User experience: Evaluate site design, speed, and usability

A site with a 40% Spam Score but excellent content, high DA, and strong topical relevance may be a better link opportunity than a site with 10% Spam Score but poor content and low relevance.

Context Matters

Spam Score interpretation varies by context:

New sites: May have higher scores due to limited history; assess growth trajectory
Niche sites: Narrow topical focus can trigger “small site structure” flags despite being legitimate
International sites: Different TLDs and linking patterns may affect scores
Industry variations: Some industries (finance, health, legal) naturally have more conservative link profiles

Use Spam Score as a Starting Point, Not a Final Answer

Think of Spam Score as a triage tool:

Low scores: Quick green light for further evaluation
Medium scores: Yellow flag requiring manual review
High scores: Red flag requiring thorough investigation or avoidance

The score directs your attention to where deeper analysis is needed, but it doesn’t make the final decision for you.

Monitor Trends Over Time

Single-point-in-time Spam Scores are less valuable than trends:

Track your own Spam Score quarterly
Watch for sudden increases (potential issues)
Monitor competitors’ scores for industry benchmarks
Note whether scores improve after addressing underlying issues

Educate Clients and Stakeholders

If you’re working with clients or reporting to stakeholders:

Explain that Spam Score is a risk indicator, not a penalty
Provide context for what the score means in practical terms
Focus on actionable improvements rather than fixating on the number
Emphasise comprehensive quality assessment over single metrics

Conclusion

Spam Score, developed by Moz, is a valuable tool for assessing potential risks in link building and backlink management—but only when properly understood and applied within a broader SEO strategy.

The key takeaways for using Spam Score effectively:

Understand what it measures: Spam Score identifies correlation with penalised sites, not causation. A high score indicates shared characteristics with penalised domains, not a guarantee of penalties.

Use appropriate thresholds: Low scores (0-30%) generally indicate minimal risk, medium scores (31-60%) require further investigation, and high scores (61-100%) warrant caution or avoidance.

Never rely on Spam Score alone: Always evaluate content quality, topical relevance, Domain Authority, traffic metrics, and user experience alongside Spam Score.

Apply context: Consider site age, niche characteristics, and industry norms when interpreting scores.

Focus on underlying quality: Rather than obsessing over the score itself, address the actual quality issues that trigger spam flags—thin content, poor internal linking, toxic backlinks, and technical SEO problems.

Monitor trends: Track your own Spam Score over time to identify potential issues early and measure the impact of improvements.

By incorporating Spam Score into a comprehensive, nuanced approach to SEO and link building, you can make more informed decisions, protect your site’s reputation, and build a backlink profile that supports long-term search visibility and authority.

Remember: Spam Score is a helpful guide, not a definitive judgment. Use it wisely, combine it with other quality signals, and always prioritise creating genuine value for your audience above all else.

Have you encountered challenges with Spam Score? Do you have questions about interpreting your site’s score or making link building decisions? Share your experiences and questions in the comments below.

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