Litmus recommends around 50 characters. Yes Lifecycle Marketing says emails with subject line up to 20 characters have ethe highest average open rate, unique click rate, and click-to-open rate. An analysis from Retention Science found that subject lines with 6 to 10 words results in the highest open rates. And Return Path advises using 61 to 70 characters.
Email marketing has the highest conversion rates of any marketing channel. In fact, sixty-six percent of online consumers made a purchase after receiving an email marketing message — which is more than social and direct mail, according to the Data & Marketing Association. And transactions from email are three times more profitable than those made on social media, reports the global management consulting firm McKinsey & Company.