Revenue per Email Sent (RPE)

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Revenue-per-Email-Sent (RPE, often called “Revenue-per-email”) is measured as a currency value; it can be as low as $0 and there is no upper limit on how high it can be. 

It is more easily calculated than Return-on-Investment (ROI) or Return-on-Ad-Spend (ROAS), as the only data required is the revenue generated and the number of emails sent. This makes it the simplest business metric; it is an appropriate and often-used key performance indicator (KPI). 

Tips for Interpreting Revenue-per-email (RPE)

RPE gives you a good read on how effectively the email message drove revenue, which is often the primary goal of an email campaign. RPE adjusts the total revenue figure so that you can do an apples-to-apples comparison, even if your send quantities are very different. 

While Revenue-per-email (RPE) isn’t as good as ROI or ROAS, it’s close. And if you’re doing A/B split testing, where the cost of goods sold and overhead are the same for both the control and test versions of your email, it’s a quick way to be able to declare a winner. 

You can also use RPE to rank your sends by most- to least-effective, giving you data to use to optimize the performance of your overall email marketing program. 

See our other articles for examples of other metrics baked-on revenue like  Return-on-Investment (ROI) or Return-on-Ad-Spend (ROAS). 

If your calculated RPE is very small — less than $1.00, say — it’s appropriate to shift to revenue-per-thousand-emails-sent (RPME) as your key metric. It’s easy to calculate, just: 

  • Divide your send quantity by 1,000 in the original equation
  • Multiple your calculated RPE by 1,000 

Related Links

Want to learn more about RPE and other revenue-related metrics? I wrote “Revenue per Email — An Advanced Email Marketing Metrics You Should Know” years ago, but the blog post is still relevant today. 

Love case studies? Here’s one on RPE: “Revenue per Email Measurement Case” and one that I wrote  about RPE and other revenue metrics, “Case Study: How the Wrong KPI Can Make Your Testing Useless…