Free Tool
Email Subject Line Tester
Paste your subject line and get an instant score, plus specific tips on length, spam triggers, and what to fix. No sign-up, no email.
Your subject line
Score
A guide, not a guarantee. The best subject lines are short, specific, and written like a human.
How the email subject line tester works
Type or paste any subject line into the box. The tester checks it against six criteria - length, word count, spam trigger words, use of caps, excessive punctuation, and whether it speaks to the reader directly. Each check either keeps your score where it is, docks points, or adds a small bonus for the things that actually help open rates.
The score gives you a fast read on what to fix. The feedback list below it tells you exactly why - so you are not just chasing a number, you are improving the line itself.
What makes a subject line get opened
Four things move the needle most:
- Short and specific. Under 50 characters. One clear idea. "3 ways to cut your CRM admin time" beats "Important information regarding your account management workflow".
- Curiosity or value - not both. Either make them curious enough to open, or tell them exactly what they get. Trying to do both usually means doing neither.
- No spam trigger words. Words like "free", "guaranteed", "act now", and "urgent" train spam filters to bin your email before it reaches anyone. They also read as try-hard to anyone who does see them.
- Written like a person. If you could imagine seeing it from a colleague or a client rather than a marketing newsletter, you are on the right track.
Automate your follow-up emails
A great subject line matters most when you are sending at volume. If you are running follow-up sequences - post-demo, post-quote, re-engagement - the subject line is the first thing that decides whether any of that work pays off.
Automation means you can test subject lines properly. Send variant A to one segment, variant B to another, and let the open rate data tell you which direction to take. Without a sequence running, you are guessing every time.
We build follow-up email automations in n8n that send the right email at the right time - based on triggers like form fills, CRM stage changes, or inactivity. No manual chasing, no emails falling through the cracks.
Read more: how to automate lead follow-up and AI email triage for Australian businesses.
Want to set up follow-up sequences for your business? Book a free 30-minute call and we will show you what is possible.