Email marketing continues to be a powerful part of most companies' strategies, but many factors can contribute to the success of an email program (text vs. email, time of day, day of the week, etc). It can be overwhelming at times to pinpoint the ideal email for your organization, and testing different combinations is often necessary.

The good news is that the London company Alchemy Worx has solved one piece of the email puzzle for us—subject line length. According to their research, response rates are highest when the subject lines are in the 50-character range or 80-character range, but they fall in the middle when the length is 60 or 70 characters. To increase open rates, keep these magic numbers in mind next time before you click send.