Email Subject Line Tester
Score your email subject line for length, spam-trigger words, caps, punctuation and engagement signals, with a live inbox preview.
Scoring checks length, word count, spam-trigger words, ALL CAPS, excessive punctuation, personalization, numbers and urgency. Heuristics based on common email-marketing guidance — always A/B test with your real audience.
Want this done for your business?
Radiatus delivers cloud, security & automation for growing teams.
Privacy & Security
Runs entirely in your browser. No data is sent to any server.
How to Use
Type your subject line to get an instant score out of 100 with specific fixes and a preview of how it truncates on mobile.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.