Email Performance Calculator
Eight campaign metrics from one set of send numbers.
Results
Nothing is required. Each metric appears once the figures behind it are filled in.
Share of sent emails that reached an inbox.
Share of sent emails that were returned undelivered.
Share of delivered emails that were opened. Inflated by privacy features like Apple MPP.
Of the people who opened, the share who clicked - content and offer quality, isolated from deliverability.
Share of delivered emails that led someone to opt out.
Share of delivered emails marked as spam. Above ~0.1% is a sender-reputation risk.
Net change in list size over the period. Negative when losses exceed gains.
Average revenue per email sent, bounces included.
Worked example
10,000 sent · 9,800 delivered · 2,450 opens 98.00% delivery · 25.00% open rate
What this number tells you
The eight metrics fall into four groups. Deliverability (Delivery Rate and Bounce Rate) asks whether the email arrived. Engagement (Open Rate and Click-to-Open Rate) asks what happened once it did. List health (Unsubscribe, Complaint and List Growth Rate) asks what the send cost you in audience. Revenue per Recipient asks what one email was worth.
They share denominators, which is why they belong on one page: delivered feeds four of them, sent three. Entering the same campaign's numbers eight separate times is how you end up with metrics that don't reconcile.
Seeing them together is what makes them readable. A low Open Rate beside a high Bounce Rate is a list problem, not a subject-line problem. A healthy Open Rate with a weak Click-to-Open Rate points at the offer. A strong Revenue per Recipient beside a rising Complaint Rate means the campaign is earning now and spending sender reputation to do it.
When to use it
After a send, to read one campaign whole rather than one metric at a time; and across sends, to see which of the four groups moved when a headline number changed.
Where it misleads
Apple Mail Privacy Protection pre-fetches images and registers opens nobody performed, so Open Rate is a trend against itself rather than an absolute. And Click-to-Open Rate is clicks over opens; reporting it as email CTR, which is clicks over delivered, answers a different question entirely.
Frequently asked questions
Why is one of the metrics blank?
Because its own inputs aren't filled in yet, or its denominator is zero. Each metric is computed independently, so Open Rate appears as soon as you enter opens and delivered, whether or not you have revenue or complaint figures. A blank result means the question isn't answerable from what you've entered; it does not mean the value is zero.
Is Open Rate still worth measuring?
As a trend against itself, yes; as an absolute number, less than it used to be. Apple Mail Privacy Protection and similar features pre-fetch images, registering opens that no person performed. That inflation is fairly stable within one audience, so period-over-period comparisons still carry signal, but comparing your Open Rate to a published benchmark from a different audience mix means comparing two different amounts of artefact.
Should Revenue per Recipient use sent or delivered?
This calculator uses sent. It is the more conservative reading: the campaign is charged for every address it attempted, including the ones that bounced. Dividing by delivered gives a higher number that answers a narrower question: what a reachable recipient was worth. Neither is wrong, but mixing the two across reports is.
My delivered count is higher than my sent count. What went wrong?
That is a data error rather than an unusual result; an email cannot be delivered without being sent. The usual causes are pulling the two figures from different date ranges, or from different segments of the same campaign. Check that both numbers describe the same send before reading anything else on the page.
What counts as an acceptable Complaint Rate?
The commonly cited threshold is 0.1%; above it, major mailbox providers start treating the sender as a reputation risk. It is a threshold to stay well under rather than a target to approach, and because the consequence arrives as degraded deliverability weeks later, a rising Complaint Rate is worth acting on before Delivery Rate reflects it.
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