Revenue per Email Calculator

The maths behind it

Revenue per email is campaign revenue divided by emails delivered: revenue ÷ delivered. It is the single most useful figure in email marketing because it collapses every rate into money.

Open rate, click rate and conversion rate all feed into it, so a change in any of them shows up here without needing to be tracked separately.

The contribution version, contribution per email; is better still, since a discount campaign can raise revenue per email while lowering what the business keeps.

Putting numbers to it

$1,392 of revenue from 11,820 delivered emails is $0.1177 per email. At a 55% margin the contribution version is $0.0647.

That figure makes decisions comparable. A segment of 3,000 producing $0.28 per email is worth four times the list average and deserves more frequent sends; one producing $0.02 is being mailed at a loss once deliverability damage is counted.

It also prices list growth directly: at $0.065 of contribution per email and 52 sends a year, each subscriber is worth $3.38 annually, so a $2 cost per acquisition pays back in seven months.

Very few email metrics convert into a decision that cleanly.

Where it is unreliable

Attribution windows inflate it. Most platforms credit any purchase within several days of a click, including ones the recipient was going to make anyway, so the figure includes revenue the campaign did not cause.

It also varies enormously by campaign type, a promotional send and a newsletter produce very different figures and averaging them describes neither.

How to act on this

Calculate it per segment rather than per campaign, and use the differences to set frequency. Segments earning several times the average can take more sends; those far below it should be mailed less or re-engaged.

Then track it as a trend. Falling revenue per email at constant list size is the earliest sign of list fatigue or deliverability decline, and it appears months before the underlying rates look alarming.

Using it to decide frequency

Increasing frequency raises total revenue and lowers revenue per email, because each additional send reaches a slightly less receptive audience and adds unsubscribes.

The optimum is where the marginal send still produces more contribution than the future value it destroys through unsubscribes and disengagement, which is calculable once subscriber value is known.

On the example list, a send producing $765 of contribution and costing 59 subscribers worth $3.38 each in future value nets $566. When a marginal send drops below that threshold, frequency has gone too far, and most businesses find the line is further out than they assumed, which is why under-mailing is more common than over-mailing.

Automated flows should be excluded from the campaign average, since a welcome sequence or an abandoned cart message earns several times what a broadcast does and inflates the blended figure.

Reporting broadcasts and flows separately makes both readable and prevents a strong automation programme from disguising weak campaign performance.

Tracking it alongside list size shows whether growth is adding value or diluting it, since a list growing while revenue per email falls is acquiring the wrong subscribers.