Email Subject Line Tester

Test and score your email subject lines before sending

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About this generator

The Email Subject Line Tester analyzes your email subject lines and scores them based on factors that influence open rates.

Get actionable recommendations for word choice, length, emotional triggers, and personalization to maximize your email performance.

Pro tips

  • Subject lines with 6-10 words have the highest open rates
  • Personalization (using the recipient's name) increases opens by 26%
  • Numbers in subject lines boost open rates by 15%
  • Avoid ALL CAPS and excessive punctuation (!!!); they trigger spam filters
  • A/B test subject lines with at least 10% of your list before full send

Frequently Asked Questions

A good subject line is 6-10 words, creates curiosity or communicates clear value, avoids spam trigger words, and accurately represents the email content. Personalization and urgency also improve performance.

Common spam trigger words include 'free', 'guaranteed', 'no obligation', 'act now', 'limited time', and excessive use of capital letters or exclamation marks. Our tool flags these automatically.

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