Subject TesterContact us

Subject line tester

Write subject lines that get opened.

Score any subject line for length, clarity, spam risk and curiosity, and see how it displays on mobile and desktop.

Test a subject lineHow it works
Subject line test
  • Length38 characters
  • Mobile previewFits
  • Spam riskLow
  • CuriosityMedium
  • Score81/100

What we do

  1. Instant score

    Feedback as you type.

  2. Preview

    See how it looks in real inboxes.

  3. Variations

    Suggested alternatives to test.

How it works

  1. 1

    Paste or upload

    Drop in your email, list or domain. No setup needed.

  2. 2

    Get results

    A clear score and line-by-line findings in seconds.

  3. 3

    Improve

    Apply suggested fixes and test again.

Get in touch

Leave your email and we will reply within one working day, or write to us at hello@subjecttester.com.