Free Email Subject Line Tester — Score & Optimize
Write email subject lines that get opened. Our free Email Subject Tester scores your subject line from 0 to 100, analyzing power word usage, length optimization (ideal is 35–50 characters), spam trigger words, question marks, number usage, and urgency signals. Get actionable tips to improve your score and maximize open rates. Essential for email marketers, newsletter writers, and anyone running email campaigns.
✦ FreeNo sign-upBrowser-onlyNo data uploaded
0 chars · ideal: 40–55
How to use the Email Subject Tester
- Open the tool — Visit this page in any browser. No account, download, or installation required. Works on desktop, tablet, and mobile.
- Enter your content — Write email subject lines that get opened.
- Get your result instantly — All processing happens in your browser. Copy, download, or share your result immediately. Your data never leaves your device.