A spam score checker runs your email through SpamAssassin-style rules and returns a number, plus a list of exactly which rules you triggered. A SpamAssassin score below 2.0 is safe for almost every mail server; 2.0 to 5.0 is moderate risk; above 5.0 gets the message rejected or filtered.
A spam score checker runs your email through SpamAssassin-style rules and returns a number, plus a list of exactly which rules you triggered. A SpamAssassin score below 2.0 is safe for almost every mail server; 2.0 to 5.0 is moderate risk; above 5.0 gets the message rejected or filtered. On mail-tester's 10-point scale, aim for 9 or 10.
Do not settle for "under 5." A score of 4.9 technically passes and still fails on the stricter server configs your recipients use. The safe target is 0 to 2 SpamAssassin points. This post covers what a spam score checker actually inspects, how to fix the common score-killers, and the one thing it cannot see: your domain reputation.
A spam score checker is a tool that evaluates an email's content, formatting, headers, and authentication against a spam-filter ruleset such as SpamAssassin, then returns a numeric score and the list of triggered rules. A lower score means fewer spam signals. It rates the message itself and does not measure sender reputation or actual inbox placement.
A receiving endpoint that scores your mail. You send your real email to the test address, the tool runs it through SpamAssassin-style rules and returns a score out of 10 with the exact rules you hit, from authentication gaps to trigger words. mail-tester is the common free one; MailerCheck, IPQualityScore, and others do the same job.
It is a content and configuration check. It tells you whether the message itself carries obvious spam signals, so you can fix them before a campaign.
SpamAssassin runs over 700 tests, grouped into four categories:
mail-tester also flags broken links, excessive images, and a missing unsubscribe header with plain-English explanations of each.
Two scales, one target.
On raw SpamAssassin points, below 2.0 is safe, 2.0 to 5.0 is moderate risk, above 5.0 is filtered or rejected. On mail-tester's 10-point display, 10 is perfect and each triggered rule subtracts. You want 9 or 10, which corresponds to roughly 0 to 1 SpamAssassin points.
Aim for 0 to 2, not 4.9. The gap matters because your recipients' servers are configured differently. A message at 4.9 clears a lenient server and gets filtered by a strict one, and you have no way to know which your prospect runs. A message at 1.0 clears both.
Run this before you save a cold email template, and most campaigns will score 9 or 10 without a second pass.
Each item maps to a SpamAssassin rule with a known point cost, so a template that passes all eight has very little room left to score badly. See cold email deliverability guide.
The score rates your message. It does not know anything about your sender reputation.
You can score a perfect 10 and still land in spam at Gmail, because Gmail is foldering you on domain reputation, complaint history, and engagement, none of which a content checker measures. This is not a contradiction. The two things measure different layers. See why are my emails going to spam, and confirm real placement with an email deliverability test or inbox placement test.
Use the spam score to remove content and configuration as suspects. If the score is clean and you are still in spam, the problem is reputation, and reputation traces back to the list.
Different numbers, often confused.
Your spam score is a pre-send content rating from a tool. Your spam complaint rate is the percentage of recipients who hit "report spam" on your real mail, measured by the mailbox provider. The complaint rate is the one that drives reputation, and the threshold is under 0.1%, never reaching 0.3%.
A clean spam score helps keep the complaint rate low, because obviously spammy mail gets reported more. But you can have a spotless score and a high complaint rate if you are emailing people who do not want to hear from you. See spam complaint rate benchmark and email domain reputation check.
The Zero-to-Two Target: a passing SpamAssassin score is under 5, but the safe target is 0 to 2 points. The margin between 2 and 5 is the range where one recipient's server delivers you and the next one's filters you.
The target exists because "the message passed" is the wrong bar. SpamAssassin's default filtering threshold is 5.0, but many mail servers lower it to 3.0 or even 2.0 for stricter environments, especially corporate gateways in front of B2B inboxes. A message you scored at 4.5 on mail-tester will be delivered to some prospects and quarantined for others, and the ones behind strict gateways are often the enterprise accounts you most want to reach.
Getting from 4.5 to 1.0 is usually quick: fix authentication, add the unsubscribe header, cut two or three trigger phrases, drop a shortened link. Each fix is a known point value, so you can see the score fall as you go. The quotable version: "A spam score under 5 means you might get in. A score under 2 means you will."
Retest after every change and stop at 9 or 10 on the 10-point scale.
A perfect spam score protects the content side. It does nothing for the reputation side, which is driven by bounces and complaints, which are driven by who is on the list.
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A spam score checker rates your email's content, headers, and authentication against SpamAssassin's ruleset and hands you a number with the triggered rules listed. Send your real message from your real mailbox, fix the highest-value hits first, and get to 0 to 2 SpamAssassin points, not just under 5, because the 2-to-5 range is where strict servers filter you. Then remember the score cannot see your domain reputation: if it is clean and you are still in spam, the problem is the list, and a verified list is the fix.
What is a good spam score on mail-tester?
Aim for 9 or 10 out of 10, which corresponds to roughly 0 to 1 SpamAssassin points. A score of 7 or 8 will still be filtered by stricter mail servers. Fix every triggered rule the tool lists, retest, and do not launch a campaign from a template scoring below 9.
What does a spam score checker measure?
It measures your email's content and configuration against a spam-filter ruleset like SpamAssassin: spammy words, formatting problems, image-to-text ratio, header structure, SPF, DKIM, and DMARC status, and link reputation. It returns a score and the list of rules you triggered. It does not measure your sender reputation or where your mail actually lands.
Why is my spam score good but my email still goes to spam?
Because the score rates your message, not your reputation. Gmail and Outlook folder mail based on domain reputation, complaint history, and engagement, which a content checker cannot see. A perfect score and a spam folder are not a contradiction. If content is clean, the cause is reputation, which comes from your list.
How do I lower my spam score?
Fix authentication first, since failing SPF, DKIM, or DMARC is the biggest hit. Add a List-Unsubscribe header, remove spam trigger phrases and money symbols, cut image weight so the email is close to plain text, replace shortened links with a custom tracking domain, and clear any blacklist listing. Each fix has a known point value.
Is a spam score the same as a spam complaint rate?
No. A spam score is a pre-send content rating from a tool. A spam complaint rate is the percentage of real recipients who mark your mail as spam, measured by the mailbox provider, and it must stay under 0.1%. The complaint rate drives reputation; the score is a content check that helps keep complaints low.
How often should I check my spam score?
Every time you create or meaningfully change an email template, and before launching any new campaign. Also recheck after changing your sending domain, signature, or link structure. It is a fast, free check, so there is no reason to run a campaign from an untested template.
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