Score your subject lines for open rate potential. Get instant, actionable feedback.
Email subject lines determine whether your message gets opened or ignored. Studies show that 47% of recipients decide to open an email based solely on the subject line. The ideal length is 6-10 words or 40-60 characters — long enough to be descriptive, short enough to display fully on mobile.
Effective subject lines create curiosity or urgency without being clickbait. Personalization (using the recipient's name or company) increases open rates by 20-26%. Numbers and specifics outperform vague promises — "5 tips to reduce churn by 30%" beats "Tips to improve your business."
Avoid common spam triggers: ALL CAPS, excessive punctuation (!!!), and words like "free," "guarantee," or "act now." Emojis can help in B2C but hurt in B2B. A/B testing is the gold standard — but this tool gives you instant feedback on length, readability, and common pitfalls before you send.
This tool in other languages:
Français:
Testeur de ligne d'objet d'email
Español:
Probador de asunto de email
Deutsch:
E-Mail-Betreffzeilen-Tester
Português:
Testador de assunto de email
日本語:
メール件名テスター
中文:
邮件主题行测试工具
한국어:
이메일 제목 테스터
العربية:
اختبار سطر موضوع البريد الإلكتروني
Type or paste your subject line. The tool analyzes length, word count, power words, urgency markers, capitalization, emoji usage, spam triggers, and personalization. You get an overall score plus specific feedback on what to tweak to improve open rates.
30-50 characters is the sweet spot. Mobile clients truncate subjects around 40 characters — longer subjects get cut off. Very short subjects (under 20 chars) often feel spammy or vague. Front-load the important words in case the rest gets truncated.
Classic triggers: FREE in all caps, !!!, GUARANTEED, act now, limited time, money symbols ($$$), and excessive exclamation. Modern filters are smarter and consider the whole message, but subject lines heavy in these phrases still get flagged more often. Use urgency sparingly and honestly.
It depends on your audience. B2C/consumer emails often see 5-15% open rate lift from emojis. B2B/professional emails often see neutral or slightly negative response — emojis can feel unprofessional. Test with your specific list. If you use emojis, one relevant one at the start or end is enough; strings of emojis look spammy.
First-name personalization shows modest lift (3-8% higher open rates) when it's done well. But personalization with no relevance feels creepy or spammy. Better: personalize with context ("Ada, here's your Q3 report") rather than just a first name. Empty name-drops feel like mail merge.