Test your email subject line before you send.

Paste your subject line and get an instant score out of 100, plus the exact things that could hurt your open rate or send you to the Promotions tab, with how to fix each one. Nothing you type leaves your browser.

100% private. This runs entirely in your browser, nothing is uploaded or stored.

Your score and a checklist of fixes will appear here.

What the tester actually checks.

A good email subject line is short, honest and written the way you would text a friend, with no spam-trigger words, no shouting and no fake urgency. This tester scores your line on the things filters and readers both react to: spam-trigger words (free, guarantee, act now), length (aim for 20 to 50 characters so it does not get cut off on mobile), ALL-CAPS and stacked punctuation, too many emoji, and deceptive "Re:" or "Fwd:" prefixes. It is a fast sanity check before you hit send. For the deeper craft, read how to write catchy email subject lines, and to check the whole email, not just the subject, use the free email spam checker.