Email Subject Lines and CTAs

Mobile email clients display approximately 30 to 45 characters of subject line text before truncating. With over 60 percent of emails opened on mobile devices, subject lines that exceed this range risk losing their core message in preview. The key value proposition must appear in the first 30 to 35 characters.

Shorter subject lines of 20 to 30 characters sometimes achieve higher open rates because they appear complete on every device and screen size. Testing your own list's response to different length ranges yields more accurate benchmarks than industry averages.

Inserting the recipient's first name in the subject line, such as Emma, your cart is waiting, typically lifts open rates by 10 to 20 percent over non-personalized versions. However, the effect diminishes with overuse. If every email opens with the recipient's name, the tactic loses its distinctiveness.

Beyond first names, consider personalizing subject lines with location-based references, product category preferences, account milestones, or purchase history. Behavioral personalization tied to what someone actually did in your app or on your website outperforms demographic personalization in most tests.