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AI Email Subject Line Tester

Test and refine your subject line so more people open your emails.

You only need to take one test to find your ideal subject line. Use cutting-edge AI analysis to test and improve your email subject lines to increase engagement and open rates.

Preparing your tool...

What to Expect from the Email Subject Line Tester?

The Email Subject Line Tester takes you from a first draft to a data-backed, high-performing subject line in just a few clicks.

  • AI-enhanced scoring

    See how your subject line stacks up against industry averages by receiving an overall score (0–100).

  • Expected performance

    Based on your subject line, see the expected engagement rate, email deliverability rate, and expected open rate range.

  • Readability analysis

    Identify complex and technical words that could make reading more difficult and select one of the suggested easier-to-understand alternatives.

  • Subject line suggestions

    Look through pre-made subject line ideas for campaigns for Mother's Day, Valentine's Day, Cyber Monday, Black Friday, Halloween, New Year's, Easter, and more.

How the email subject line tester works?

  • 1

    Type your subject line

    Paste or type the email subject line into the text box.

  • 2

    Click the Analyze button

    Get your score and readability analysis in a comprehensive report in seconds.

  • 3

    Get improvement ideas

    Check the detailed breakdown and AI-driven insights that guide your next move.

Why use a Subject Line Tester?

  • Boost open rates

    47% of email recipients open an email based on the subject line alone. The perfect subject line can boost email open rates by knowing what works before you send.

  • Save time

    Get actionable insights and ready-made suggestions instead of guessing what works.

  • Backed by data

    Avoid guesswork and create subject lines backed by data

  • Improve deliverability

    Avoid spam filters and earn trust by increasing engagement with subject lines designed to capture attention.

Take your subject lines further with beautiful email templates.

Once you’ve tested your subject line here, try pairing it with one of Designmodo’s ready-made email templates to see the difference it makes.

A subject line is what gets your email opened but what happens next is just as important. If the inside of your email doesn’t match the promise of your subject line, you risk losing your reader’s attention.

That’s where Designmodo’s ready-made email templates can help. They’re easy to customize, look great on any device (62% of recipients will delete or ignore an email if it’s difficult to read on their phone due to not being mobile responsive), and save you the time of designing from scratch.

Your subject line and a smooth email template together give your emails the best chance to perform higher opens, more clicks, and a better connection with your audience.

Explore Email Templates

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