50 is the example result. Read it using the units and relationship stated below.
Cost Per Acquisition (CPA) uses campaign spend, conversions.
Separating campaign efficiency from business profit
For cost per acquisition (cpa), the relationship is Result = (([Campaign spend]) ÷ ([Conversions])). The amount depends on the supplied campaign spend, conversions, rather than a live market price or a value imported from another record. 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 cost per acquisition (cpa), retain Campaign spend, Conversions 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
Campaign spend: 5000; Conversions: 100. Result: 50. The values are illustrative.
Compare one changed input
Campaign spend changes from 5000 to 5500. The result becomes 55. All other inputs remain fixed.
Calculation rule
Result = (([Campaign spend]) ÷ ([Conversions]))
Inputs and output
| Input | Example value | Entry convention |
|---|---|---|
| Campaign spend | 5000 | Use campaign spend on the currency and period basis shown by the formula. Keep gross amounts, net amounts and unit amounts distinct; the page does not fetch a price or exchange rate. |
| Conversions | 100 | Use the source quantity represented by conversions. Keep the counted population fixed and avoid mixing a unit value with a period total. |
Output: 50 is the example result. Read it using the units and relationship stated below. Use the formula to distinguish a cash amount, count, percentage or ratio.
How to use the page
Collect the inputs
Gather Campaign spend, Conversions. 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 Campaign spend 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 50.
Change Campaign spend from 5000 to 5500 while keeping every other value fixed. The result becomes 55. 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