“Six to 10 words is the optimal length for email subject lines, ranking highest for open rates (21 percent). Second highest is zero to five words, with a 16 percent open rate. The rates start to fall significantly in the 11 to 15 – word range, with emails only opened 14 percent of the time. Anything longer than that causes the open rates to drop further.”
If you’re not sure what to say in your email subject line, you’re in luck. Using fewer words has been proven most effective with consumers. So when it doubt, cut words out and keep the language tight and focused.