Understanding Your Email Subject Tester Score

Inside the Email Subject Scoring Engine

A great email that nobody opens delivers zero value. The Email Subject Tester analyzes your draft subject line across multiple algorithmic factors to predict deliverability, mobile display clipping, and open propensity.

The Four Core Metrics

• Character & Word Count (Optimal: 30–50 characters): Most mobile email clients (Apple Mail, Gmail on iOS/Android) truncate subject lines longer than 45–50 characters. The tester flags long lines that risk losing their key hook before the fold.
• Spam Trigger Detection: Evaluates your copy against known spam filters. Overused gimmicks like excessive exclamation marks, ALL-CAPS words, and high-risk terms ("FREE", "ACT NOW", "100% GUARANTEED") will lower your score.
• Emotional Resonance & Sentiment: Checks whether your copy evokes urgency, curiosity, or value. Completely neutral subject lines often blend into inbox clutter.
• Preview Text Alignment: Assesses whether the subject line pairs naturally with a supporting preheader snippet to double your inbox real estate.

Interpreting Your Score

Scores range from 0 to 100:

• 85–100 (Excellent): Crisp, focused, mobile-optimized, and free of spam flags. Ready to broadcast.
• 70–84 (Good): Solid, but could benefit from minor trimming or stronger verb selection.
• Below 70 (Needs Work): Likely too long, overly generic, or triggering spam heuristics. Use the suggested alternative variations to improve.