Knowledge database: How to interpret spam filter scores

Q: What is a spam filter score and how is it calculated?

A spam filter score is determined by the ratio of emails landing in your inbox versus those routed to the spam folder. The higher the score, the greater the proportion of messages flagged as spam. This metric helps senders gauge their email deliverability performance.

Q: What does a high spam filter score mean for email deliverability?

A high spam filter score indicates that a larger number of your emails are being classified as spam rather than reaching recipients' inboxes. This signals a significant deliverability problem that needs to be addressed to ensure your messages are seen by your audience.

Q: Which spam filter companies does MailMonitor cover in their spam score guide?

MailMonitor's free guide covers spam filter scores from four major companies: Spam Assassin, Symantec, Barracuda, and Brightmail. The guide was prepared by their deliverability experts to help users interpret scores from each of these filtering systems.

Q: How can I prevent my emails from going to spam based on spam filter scores?

Understanding how spam filters like Spam Assassin, Symantec, Barracuda, and Brightmail score your messages is the first step toward keeping emails out of the spam folder. MailMonitor's deliverability experts offer a free knowledge database guide that explains how to interpret these scores and take corrective action to improve inbox placement.

August 19, 2025

It’s time to put on our referee hats and take a look at those Spam filter scores.

First of all, let’s talk about the term: Spam Filter Scores.

To put it simple, this score is determined by the number of emails that land either in your inbox compared to the number of emails that land in the spam folder. The higher the score is, the larger is the number of spam emails.

Our deliverability experts prepared this Free Guide to help you understand spam filters and prevent your emails from going to Spam. We’ll interpret the Spam Filter Scores of these four companies: Spam Assassin, Symantec, Barracuda and Brightmail.

Go get a free copy of our knowledge database edition explaining in a simple way how to interpret spam filter scores. Learn more.

What is a spam filter score and how is it calculated?

What does a high spam filter score mean for email deliverability?

Which spam filter companies does MailMonitor cover in their spam score guide?

How can I prevent my emails from going to spam based on spam filter scores?

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