SpamAssassin Score Checker: Test & Lower Your Email Spam Score

Campaign Cleaner runs your email through SpamAssassin and shows you exactly which rules are firing, what your score is, and what to fix - so you can clean up issues before your campaign goes out.

What Is SpamAssassin and How Does It Work?

SpamAssassin is the world's most widely deployed open-source spam filtering engine. Developed under the Apache Software Foundation, it is used by millions of mail servers, hosting providers, and ISPs to evaluate incoming email before delivering it to recipients. Rather than making a binary spam/not-spam decision, SpamAssassin assigns a numerical score to every message based on how many rules it triggers and how much each rule contributes. Mail server administrators set their own threshold - most use the default of 5.0 - and any message exceeding it is filtered or rejected.

How Is a SpamAssassin Score Calculated?

SpamAssassin evaluates hundreds of individual rules and adds their point values together. Rules are organized into categories covering content (words, phrases, formatting), headers (From, Subject, MIME structure), authentication (SPF, DKIM, DMARC), and URL reputation (known malware or phishing domains). Rules that indicate spam contribute positive points; rules that indicate legitimate email can subtract points. The final score is a sum of all positives and negatives combined. A score of 0.0 to 2.0 is clean, 2.0 to 5.0 is borderline, and anything above 5.0 will be treated as spam on most servers.

What Score Should Your Email Aim For?

While a score below 5.0 technically passes the default threshold, that margin is too thin for reliable inbox placement across the variety of server configurations your recipients use. Some mail administrators set their threshold as low as 3.0. Corporate mail gateways and security appliances often apply their own additional layers on top of SpamAssassin. Targeting a score below 2.0 gives your email a safe buffer that accounts for these stricter configurations. Campaign Cleaner shows your exact score and breaks down each contributing rule so you know specifically what is raising it and by how much.

The Most Common SpamAssassin Rules That Fire in Marketing Email

Marketing emails routinely trigger SpamAssassin rules in several categories. The highest-frequency offenders are:

• HTML formatting problems: Excessive font size changes, hidden text, mismatched background colors, or inline styles that resemble obfuscation techniques used by spammers.
• Spam keyword density: High concentrations of urgency language, financial offers, or promotional superlatives that match known spam patterns.
• Missing plain-text version: Legitimate email almost always includes both HTML and plain-text parts. HTML-only messages trigger a scoring penalty.
• Suspicious URL patterns: URLs using IP addresses instead of domain names, excessively long redirect chains, or domains on known blocklists.
• Authentication failures: Missing or failing SPF, DKIM, or DMARC records add points to the score and reduce the email's trustworthiness signal.

How to Lower Your SpamAssassin Score

Reducing your score requires addressing whatever specific rules are firing in your email. The most impactful actions are:

• Run your email through Campaign Cleaner to see the exact rules firing and their point contributions before you send.
• Fix HTML quality issues - ensure font sizes are consistent, no text is hidden with matching foreground/background colors, and your structure is clean.
• Reduce keyword density by substituting high-risk urgency language with specific, factual statements.
• Always include a plain-text version of your email alongside the HTML version.
• Verify your authentication records are properly configured - SPF, DKIM, and DMARC all have positive effects on scoring.
• Audit your links to ensure none point to domains on reputation blocklists or use suspicious redirect patterns.

Frequently Asked Questions