Email Subject Line Tester
Analyze your email subject lines to improve open rates. Get instant feedback, AI-powered suggestions, and mobile previews.
Master the First Impression
Your subject line decides whether your email gets opened or ignored. Our free tester uses data-backed rules and AI to help you write headlines that demand attention.
Why Test Your Subject Line?
Boost Open Rates
35% of recipients open emails based on the subject line alone. A higher score here means more eyes on your content.
Avoid the Spam Folder
We check for “spam trigger words” (like Free, Guarantee, Urgent) that can hurt your deliverability.
Mobile Optimization
Over 50% of emails are read on mobile. Our tool shows you exactly where your text will get cut off on smaller screens.
3 Ways to Write Better Subject Lines
Keep it Short
Aim for 40-60 characters. Long subject lines get truncated, hiding your most important message.
Use Power Words
Words like “Exclusive,” “Update,” and “Introducing” trigger curiosity. Our tool highlights positive keywords for you.
Leverage AI
Stuck? Use the AI Improvements feature in this tool to instantly generate 3 creative alternatives.
Action plan
Your Subject Line is Perfect. Now, Will It Land in the Inbox?
Ensure your prospect will see and open your emails. From technical setup with DMARC and SPF to using email warmup, deliverability is a complex topic. No worry, we can advise you on where to start.
Audit your current email setup
Get a complete, personalized action plan for your entire emailing system, from technical setup and list building to a full deliverability scorecard.
Take the 5-min Assessment