16.00% is the example result. The converted events must belong to the eligible visitor or prospect population. Decide whether repeat events or unique people are counted.
Calculate recorded unique opens as a percentage of delivered emails. The ratio describes the entered tracking count, not verified reader attention.
Separating campaign efficiency from business profit
The converted events must belong to the eligible visitor or prospect population. Decide whether repeat events or unique people are counted. Campaign ratios depend on the event being counted. A click, a submitted form, a qualified opportunity and a paying customer are separate outcomes. Combine spend and events from the same campaign window before comparing acquisition costs.
Source and result record
For email open rate, retain Unique opens, Delivered emails together with the output. Record the date of the source values and the unit convention used in the form. That record separates a change in the underlying case from a change in how the information was entered. A saved result without its source values cannot show which assumption produced it.
Example with the supplied inputs
Unique opens: 3200; Delivered emails: 20000. Result: 16.00%. The values are illustrative.
Compare one changed input
Unique opens changes from 3200 to 3520. The result becomes 17.60%. All other inputs remain fixed.
Calculation rule
Result = (([Unique opens]) ÷ ([Delivered emails])) × 100
Inputs and output
| Input | Example value | Entry convention |
|---|---|---|
| Unique opens | 3200 | Use the source quantity represented by unique opens. Keep the counted population fixed and avoid mixing a unit value with a period total. |
| Delivered emails | 20000 | Use the source quantity represented by delivered emails. Keep the counted population fixed and avoid mixing a unit value with a period total. |
Output: 16.00% is the example result. The converted events must belong to the eligible visitor or prospect population. Decide whether repeat events or unique people are counted. Use the formula to distinguish a cash amount, count, percentage or ratio.
How to use the page
Collect the inputs
Gather Unique opens, Delivered emails. Use one period and the units shown in the form.
Run the calculation
Enter the values and select the action. The calculation rule above explains how the inputs produce the result.
Compare a scenario
Change Unique opens on its own, keeping the other inputs fixed. Read both results before changing another assumption.
Worked example
With the example inputs listed above, the result is 16.00%.
Change Unique opens from 3200 to 3520 while keeping every other value fixed. The result becomes 17.60%. This comparison isolates that input; it does not forecast how other variables will respond.
Check the stated formula, units and limits before using the result in a decision.
Keep the displayed formula, input units and model scope with the result. Corrections or questions can be sent through the request section on this page.
Content updated: October 11, 2026