Test your email subject lines for spam words, power words, and effectiveness. Get an open rate score and A/B variations. Free email subject line analyzer, no signup.
A marketing coordinator in Chicago sends a weekly newsletter to 15,000 subscribers with a consistent 18% open rate and wants to break 25%.
Result: Analyzer reveals her subject lines average 67 characters — too long for mobile. Shortened versions tested — open rate hits 27% within 3 weeks.
A SaaS sales rep in Atlanta sends 80 cold emails per day with a 9% open rate and needs to know why prospects are not even opening.
Result: Analyzer flags 4 spam words including 'free trial' and 'guaranteed' — cleaned subject lines lift open rate to 19% in week one.
A Shopify store owner in Florida sends promotional emails with subject lines like 'SALE 50% OFF TODAY ONLY' and wonders why they hit spam.
Result: ALL CAPS and multiple exclamation points flagged — rewritten subject line with power words but no triggers improves deliverability 40%.
Great subject lines are under 50 characters, create curiosity or urgency, avoid spam trigger words, use power words, and are personalized when possible. Our analyzer scores all these factors.
Spam trigger words include terms like 'free money', 'click here', 'guaranteed', 'no risk', and 'act now'. Our tool checks your subject line against 200+ known spam trigger words.
Keep subject lines under 50 characters for optimal mobile display. Most email clients cut off subject lines after 40-60 characters. Our tool shows a real mobile preview.
Average email open rates vary by industry — generally 20-30% is considered good. A compelling subject line is the single biggest factor in improving your open rate.
Power words trigger emotional responses and drive action. Examples include 'exclusive', 'secret', 'proven', 'instant', 'limited', and 'new'. Our tool highlights them in your subject line.
Yes — every FreeFixo tool, including the Free Email Subject Line Analyzer, is 100% free with no paywall, no premium tier, and no usage limits. You do not need to create an account, enter a credit card, or share an email.