π§ Email Subject Line Tester
Score your email subject line, detect spam words, preview inbox appearance, and A/B compare variants.
How the Subject Line Tester Works
Enter your email subject line and get an instant score out of 100 based on length, word count, spam triggers, personalization, and best practices. All analysis runs in your browser.
Scoring Criteria
- Character count β Optimal range is 41-50 characters
- Word count β 6-10 words is the sweet spot for open rates
- Spam trigger words β Penalized for words that trigger spam filters
- Personalization β Using tokens like [name] boosts engagement
- Emoji usage β A single emoji can increase open rates by 56%
- Numbers β Subject lines with numbers tend to perform better
- ALL CAPS β Penalized as it triggers spam filters and reduces trust
- Excessive punctuation β Multiple !!! or ??? are flagged
A/B Comparison
Enter two subject line variants to see scores side by side. The tool highlights which one is stronger and why.