What Is Spam Score?

Definition

A spam score is a numerical rating assigned to an email based on how likely it is to be flagged as spam by filters. The higher the score, the greater the chance that the email will land in the recipient’s junk or spam folder instead of their inbox.

Email service providers (ESPs) and spam filters use a combination of algorithms, blacklists, and rule-based systems to evaluate every message. The spam score is a quick way to assess your email’s compliance with best practices and whether it raises any red flags that might hurt your deliverability.

Example

A travel agency prepares a summer promo email campaign. Before launching, they run it through a spam check tool that flags their subject line: “FREE TRIP!!! ACT FAST!” It also highlights missing SPF authentication and an overly image-heavy layout. By swapping the subject to “Summer Getaways Just Got Better,” adding proper SPF records, and including more balanced content, they lower their spam score.

Factors That Influence Spam Score

Multiple variables can increase your spam score, including:

• Lack of authentication: Missing SPF, DKIM, or DMARC records make it hard for inbox providers to verify your identity.
• Poor sender reputation: If you’ve had high bounce rates, spam complaints, or engagement drop-offs in the past, your IP address or domain may be blacklisted.
• Spammy language: Using all caps, excessive exclamation marks, or trigger words like “FREE!!!” can set off filters.
• Broken or misleading links: URLs that redirect, expire quickly, or appear suspicious can affect scoring.
• Low-quality HTML: Poor code structure, too many images without alt text, or a lack of plain-text version can raise red flags.
• Purchased or outdated lists: Sending to unverified or stale contacts often leads to high bounce or complaint rates.

How to Lower Your Spam Score

Start by authenticating your domain using SPF, DKIM, and DMARC protocols. These validate your emails and signal to inbox providers that you're a legitimate sender. Next, review your subject lines and email copy for overly promotional or aggressive language. Spam checkers help catch problematic phrases before you hit send.

Also, pay close attention to your list hygiene. Regularly remove inactive or bounced email addresses and avoid buying third-party lists. Make sure all your recipients have opted in and are still engaged. Additionally, format your emails with clean, responsive HTML and always include a plain-text version to accommodate different mail clients.

Related terms

• Spam Trap
• Sender Score
• Email Blacklist

Related articles

• Common Spam Traps to Avoid
• How to Check Email Sender Reputation
• How to Improve Email Deliverability