One number, three jobs
Revenue per delivered email is the cleanest health metric an email program has: total email revenue divided by total emails delivered. It does three different jobs at once. Per email, it benchmarks your program (ordinary promotional campaigns across the industry land near 10 cents per delivered email). Per campaign, it prices the next send before you plan it. And per subscriber per year, it becomes the input for a bigger question: what a new signup is worth, which is exactly the number our email signup value calculator asks for in its cross-check.
The honesty rules from the rest of this cluster apply here too. Revenue is not profit, so the margin field converts every figure to what you actually keep. And attributed revenue is generous by construction: your platform credits email for orders that clicked an email on the way to a purchase that may have happened anyway, so treat these numbers as email's ceiling, not its floor-to-ceiling contribution.
The formula
Per subscriber per year = (Revenue ÷ Recipients) × 12 ROI = (Revenue × Margin − Cost) ÷ Cost
Recipients stands in for your active list, which is fair as long as most campaigns go to most of the list; if you segment heavily, use the average actually mailed.
Worked example
A shop attributes $5,400 a month to email, from 8 campaigns averaging 15,000 recipients: 120,000 emails delivered, so 4.5 cents per email, against the 10 cent industry anchor. Each campaign earns $675, and each subscriber produces $0.36 a month: $4.32 a year.
At a 60% margin that is 2.7 cents of profit per email and $2.59 of profit per subscriber per year. Against an $800 monthly program cost (platform plus hours), email clears 5,400 × 60% − 800 = $2,440 a month: $6.75 of revenue per $1 of cost, a 305% ROI on a profit basis.
The 36 to 1 legend, and the two animals in your average
The most quoted statistic in email marketing says the channel returns $36 or more for every $1 spent. The figure comes from industry surveys: self-reported revenue divided by self-reported cost, averaged across respondents who bothered to answer. It is not fake, but it is a revenue-basis average with soft denominators, and comparing your honest profit-basis ROI against it is how a genuinely healthy program gets mislabeled a failure. The example above returns $6.75 per $1 and makes $2,440 a month. That is not losing to the benchmark; that is running a real program while the benchmark runs a survey.
The second honest caveat: your average mixes two different animals. Automated flows (welcome series, abandoned cart reminders) earn on the order of 18 times more per recipient than promotional campaigns, and across the industry they produce roughly 40% of email revenue from about 5% of sends. If your revenue figure includes flows, your campaign RPE looks better than it is; if you have no flows yet, the single highest-leverage move in email is not another Tuesday newsletter, it is switching on the welcome series and the abandoned cart reminder and letting them run. Our cart abandonment calculator prices the second one honestly before any vendor does it dishonestly.