Email Subject Tester
Score your email subject line against deliverability and engagement best practices.
0 charactersideal
Type or paste your email subject line above to get a score and recommendations
FAQ
- What is the ideal email subject line length?
- Aim for 40–50 characters to ensure your subject displays fully on most mobile devices. Subjects over 70 characters are truncated on many clients. Shorter subjects (under 20 characters) can seem vague. The sweet spot is a concise, descriptive subject under 50 characters.
- Do spam trigger words always cause spam filtering?
- Not always — modern spam filters use machine learning and consider many signals beyond keywords. However, words like "free", "urgent", "winner", "act now", and "limited time offer" increase the likelihood of being flagged, especially when combined with ALL CAPS, excessive punctuation, or high image-to-text ratios.
- Should I use emojis in subject lines?
- Emojis can increase open rates when used sparingly and relevantly. However, they may render as garbled characters in older email clients. Use one emoji maximum, ensure it adds meaning (not just decoration), and test across clients. Avoid using emojis as substitutes for words.
Analyse an email subject line against key quality factors: character count (optimal 50, max 70), emoji detection, ALL CAPS percentage, common spam trigger words (free, urgent, act now, winner, limited time), and preview text length. Get an overall score out of 100 and specific recommendations for improving deliverability and open rates.