Score your cold email subject lines and get actionable tips to boost open rates
The best cold email subject lines are short (under 50 characters), personalized with the prospect's name or company, and avoid spam trigger words like "free" or "act now." Studies show that subject lines with questions get 10-20% higher open rates, while lowercase subject lines feel more personal in B2B outreach. Use this free email subject line tester to score every subject line before you hit send — improving your cold email open rates and deliverability across Gmail, Outlook, and other email clients.