Free Email Subject Line Tester

Test email subject lines for character count, spam trigger words, emotional sentiment, and personalization. Preview on Gmail and Apple Mail.

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How to Use

Gmail & Apple Mail preview

Character count validation

Spam trigger word detection

Personalization suggestions

What is the ideal subject line length?▾

For mobile optimization, aim for 30-50 characters. Gmail truncates around 70 characters on mobile and 90 on desktop.

What spam words should I avoid?▾

Common spam triggers include ALL CAPS, excessive exclamation marks, and words like 'FREE', 'GUARANTEE', 'ACT NOW', and 'LIMITED TIME'.

Does personalization improve open rates?▾

Yes. Including the recipient's name or location in the subject line can increase open rates by 10-20%.