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Zeta GlobalHow SpamAssassin scores an email
Apache SpamAssassin is the most widely used open-source spam filter. It runs hundreds of tests on every message, adds points for each spam sign it finds and subtracts points for good ones. When the total reaches the threshold, 5.0 by default, the message is marked as spam. The SpamAssassin score checker above runs content rules modelled on these tests, so you can see which ones your email triggers before you send it.
How the SpamAssassin score adds up
SpamAssassin looks at four kinds of evidence. Header tests check the subject line, sender details and formatting, for example a subject written in capitals. Body tests read the text and HTML: image-heavy layouts with little text, HTML with no plain-text part, phrases common in spam. URI tests look up the links in your email against domain blacklists. Network tests check your sending IP against blacklists and verify SPF and DKIM, and a valid DKIM signature earns negative points. Many installations also run a Bayes filter trained on mail its users marked as spam. Our checker covers the content rules only, which is why the result is an estimate.
What is a good SpamAssassin score
Below 0 means your email earns more trust signals than spam signals, which is typical for short personal messages. Between 0 and 2.5 is comfortably safe. From 2.5 to 5.0 the email still passes, but one extra rule from a different server, such as a blacklisted link, can push it over. Above 5.0 the email is marked as spam on a default setup, and some administrators lower the threshold to 3 or 4.
SpamAssassin rules that trigger most often
The rules we see most often are missing unsubscribe links, a single large image with little text, HTML-only messages, link shorteners, subjects in capitals or with several exclamation marks, mismatched link text and URL, and free-mail sender addresses on bulk mail. Each rule in your result comes with a plain-English fix. For wording problems, the Template Checker and our list of words that trigger spam filters help rewrite the copy.
Who uses SpamAssassin
SpamAssassin is built into cPanel hosting and runs on many corporate mail gateways and self-hosted servers, so plenty of business inboxes sit behind it. Gmail, Outlook and Yahoo use their own filters, which weigh sender reputation and recipient engagement far more than content. A clean SpamAssassin score is a good sign, but it doesn't predict placement at the big providers on its own.
Next step after a clean score
Content is one part of the decision. Run a free Email Deliverability Test to see where your email lands at Gmail, Outlook and Yahoo, and check your sending IP with the Blacklist Checker. Warmy covers the rest: it warms up your mailboxes with real engagement and tests placement before every campaign.
Clean content is half the battle. Warmy builds the reputation that does the rest. Start a 7-day trial or book a demo.
