Email ROI Calculator

How the number is derived

Return on investment for email is (contribution generated − cost) ÷ cost, where cost includes the platform subscription, the time spent producing campaigns, any design or copywriting, and the acquisition cost of the subscribers themselves.

The last item is the one usually omitted, and it is frequently the largest. A list did not appear for free.

Excluding it produces the extraordinary ROI figures the channel is famous for, which describe the sending rather than the programme.

An example

$18,100 of monthly email revenue at a 55% margin is $9,955 of contribution. Platform costs $340, production time 24 hours at $45 is $1,080, $1,420 of direct cost.

That gives an ROI of 601%, which is the figure the channel is usually quoted at.

Now include acquisition: 640 new subscribers a month at $4 each is $2,560. Total cost $3,980 and ROI falls to 150%.

Both numbers are defensible and only the second describes the business, because without the acquisition spend the list would shrink and the revenue with it.

What the number leaves out

The famous industry ROI figures, often quoted at 3,600% or similar, exclude list acquisition entirely and count attributed revenue rather than incremental revenue. They describe the marginal cost of sending an email, which is nearly zero.

That is true and not useful. The marginal cost of sending is not the cost of having something to send to.

What this changes

Include subscriber acquisition in the cost base. It converts email from an implausible outlier into a channel that can be compared honestly against paid acquisition.

Then measure incrementality at least once, by holding out a segment from a campaign and comparing purchase rates. The difference between attributed and incremental revenue in email is usually substantial, because the audience already buys.

Why email still wins even measured honestly

At 150% ROI including acquisition, email remains one of the strongest channels available, and its advantage compounds in a way paid channels do not: a subscriber acquired once can be mailed for years at nearly zero marginal cost.

That is the genuine case for the channel, and it is a better one than the inflated figures, because it survives scrutiny and it points at the right activity, acquiring good subscribers rather than sending more emails.

The businesses that get the most from email are generally those that treat list building as the investment and sending as the harvest. Those that treat sending as the activity end up mailing a decaying list more often and watching the returns fall.

Agency and freelance costs belong in the same calculation as internal time, and for a small business they are frequently the largest line in the channel.

Comparing the all-in cost against the contribution generated is what determines whether outsourcing the programme is earning its fee or simply producing more sends.

Attribution settings are worth checking rather than accepting, since a default window of several days credits email with a great deal it did not cause.

Email return on investment is reported as extraordinarily high across the industry, and the reason is partly attribution. Last-click credit assigns the full order to the email that preceded it, including orders from customers who were going to buy anyway. The figure is genuinely good and it is not the multiple usually quoted, and a holdout test is the only way to know your own.