Estimating the revenue of an e-mail marketing campaign requires a combination of factors. These include the size and quality of your e-mail list, the relevance of your message to your audience, the strength of your call-to-action, and your ability to convert leads into paying customers. To estimate the revenue of your e-mail marketing campaign, you will need to: determine your conversion rate, determine your average order value, estimate your e-mail list size, determine your e-mail open rate, and calculate potential revenue.