The true bill for one more email.

Why platform revenue overstates a send. Your platform credits a send with every purchase that follows it. Some of those customers were going to buy anyway. And extra sends often borrow from your other emails: the purchase happens a few days earlier, off a different message. The receipt takes both out to find the revenue the send itself creates.

Why a lost subscriber has a price, measured the same way. Everyone who unsubscribes or complains is gone from your email for good. That doesn’t mean losing the customer, so the tool counts only the new revenue email would have earned from them: your annual email revenue, divided by your whole list and by 12, times how long people usually stay. It takes out the same “would have bought anyway” share as the send, so both sides of the bill are measured alike. Measuring them differently would tilt the answer one way.

Why deliverability is a gauge, not a price. Gmail asks senders to keep spam complaints below 0.1% and never to reach 0.3%. Above that line, reaching the inbox gets harder for every email you send. There’s no honest way to price that, so the receipt shows where you stand instead, and at 0.3% or above the verdict says don’t send to the full list. Gmail counts complaints from its own users, which your platform can’t fully see, so Google Postmaster Tools is the better figure if you have it.

Which numbers are assumptions. Lines marked * on the receipt use an assumption, and every assumption is written out as a sentence beside the result, where you can change it. The biggest is how much revenue would have happened anyway. A holdout test measures it for your programme: choose “I’ve run a holdout” and enter what yours found.

What it leaves out. Quiet fatigue in people who stay subscribed but stop reading, effects on your brand, and channels other than email. It’s built for ecommerce, where revenue comes from purchases.