Marketing KPI

Cost per Acquisition Formula

Learn what Cost per Acquisition means, how to calculate it in Excel, and how to recreate the same KPI as a Power BI DAX measure.

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Quick answer

Cost per Acquisition is calculated as:

Campaign Cost / New Customers

Use this Excel version when your inputs are on row 2:

=IFERROR(B2 / C2,0)
Example result$37.50
FormatCurrency
Typical chartLine chart for monthly trend; bar chart for category comparison; KPI card for the latest value.

What is Cost per Acquisition?

Cost per Acquisition measures the cost connected to a business result. It helps show whether the result is efficient enough to justify the money spent.

Marketing KPIs connect campaigns, traffic, leads, customers, and revenue so you can see what actually produces results.

Beginner tip: A KPI is not just a formula. It is a number used to make a decision. Before adding it to a dashboard, write down the definition, time period, owner, target, and data source.

Real-life example

Imagine a marketing manager comparing channels at month end. The team adds the inputs for Cost per Acquisition to a campaign performance dashboard, calculates the KPI for the current month, and compares it with the previous month and target. In the sample below, the result is $37.50. That number becomes useful when everyone uses the same formula each month.

Excel cellInputWhat it meansSample value
B2Campaign Costthe cost included in the calculation for the same period as the output$9,000
C2New Customersthe count of customers or users that match the KPI definition240
ResultCost per AcquisitionOutput of the KPI formula$37.50

How to calculate Cost per Acquisition in Excel

  1. Create one row per reporting period, team, product, campaign, location, or customer segment.
  2. Add one input per column. Do not combine inputs in the same cell.
  3. Paste the Excel formula in the KPI result column.
  4. Format the result as Currency.
  5. Copy the formula down the table and compare the result against target, previous period, and trend.
Quality check before publishing:
  • Use the same date range for every input.
  • Confirm that the denominator is not blank or zero.
  • Document whether the KPI is calculated before or after discounts, refunds, taxes, returns, or cancellations.
  • Keep the definition stable so reports remain comparable over time.

Power BI DAX measure

If you also report this KPI in Power BI, create a measure instead of hard-coding the calculation in a visual. Replace the measure names below with the names used in your model.

Cost per Acquisition = DIVIDE([Campaign Cost], [New Customers], 0)

For best results, build base measures first, such as revenue, cost, customers, orders, or tickets, and then build the KPI measure from those base measures.

How to read the result

Lower is usually better, because this KPI often represents cost, waste, delay, risk, loss, or friction.

Do not read the KPI alone. A single value can be misleading without a target, trend, segment, and business context. For example, the same result may be good for one product line but poor for another.

Useful comparisons

  • Current month versus previous month.
  • Actual result versus target or budget.
  • By channel, product, customer segment, team, or location.
  • Rolling average over several periods to smooth one-off spikes.

Common mistakes

  • Mixing time periods, such as monthly cost with quarterly revenue.
  • Using a total when the KPI should be segmented.
  • Changing the formula definition after the dashboard is already in use.
  • Comparing two teams that collect the inputs differently.
  • Ignoring blanks, zeros, refunds, cancellations, or duplicate records.