Email marketing consistently delivers the highest ROI of any digital channel — but only if you can measure it. This week we cover the specific metrics that prove the business case for your email program.
This Week’s Lesson
The headline stat: DMA and Litmus research both estimate email marketing ROI at $36-42 per dollar spent. But that average masks a huge range. Well-managed programs with tight attribution can show 100:1 ROI. Poorly tracked programs appear to contribute almost nothing — not because they don't perform but because the measurement is broken.
Revenue per email sent (RPE): total revenue attributed to a campaign ÷ total emails sent. Typical range: $0.05-$0.50 for newsletters. $0.50-$5.00 for promotional campaigns. $2.00-$20.00+ for highly targeted behavioral triggers. RPE is the simplest metric to calculate and the easiest to present to leadership.
Email-attributed revenue: the sum of revenue from all purchases where an email interaction (open, click, or attribution window) occurred in the path. Requires UTM parameters and analytics integration. Report both 'email-as-last-touch' and 'email-in-path' to show full contribution.
List value: total annual email-attributed revenue ÷ average list size. This gives you 'value per subscriber per year' — a useful number for justifying list acquisition investment. If each subscriber is worth $15/year, acquiring a subscriber at $2 CAC is a 7.5x return.
Churn impact: compare the renewal rate of highly email-engaged customers vs. low or non-engaged customers. In most subscription businesses, email engagement is a leading indicator of retention — meaning email investment directly reduces churn.
Report these metrics quarterly to leadership alongside the investment (team time, ESP costs, production costs). The ratio tells the story. Teams that can quantify email ROI get resources. Teams that can only report vanity metrics get cut.