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CPA Calculator - Calculate Cost Per Acquisition

Calculate cost per acquisition from advertising spend and conversions, then compare your average CPA with an optional target CPA.

Ad Spend, Conversions and Target CPA

Define the conversion action before calculating CPA. A lead, purchase, booked call and new customer can have very different economic value.

Use the cost associated with the same conversion actions and reporting period.
Enter the conversions counted in the same advertising scope.
Enter your own acceptable average CPA for target comparison and scenario planning.
Average CPA (Cost Per Acquisition)-
Conversions per $1,000 Spent-
Cost Allowed for Current Conversions at Target CPA-
Cost Gap vs Target CPA-
Conversions Supported by Current Spend at Target CPA-
Conversion Gap vs Target Efficiency-
Target Comparison-

Example: $50 CPA vs $45 Target

Advertising cost: $5,000

Conversions: 100

Average CPA: $50.00

Conversions per $1,000: 20.00

Target CPA: $45.00

Allowed cost for 100 conversions: $4,500

Current cost gap: $500 over target

Conversions at $45 CPA with same spend: 111.11

The sample inputs shown here match the default calculator values so the example can be reproduced directly.

CPA Calculator Formulas

CPA = Advertising Cost / ConversionsConversions per $1,000 = ($1,000 / CPA)Allowed Cost at Target CPA = Conversions x Target CPAConversions at Target CPA = Advertising Cost / Target CPA

Input Checklist

Same scope: Match advertising cost with conversions from the same campaign or account segment.Defined action: Keep the selected purchase, lead, signup or other conversion definition consistent.Comparable period: Use the same date range and attribution basis, and allow for conversion delay when comparing recent periods.

Add This CPA Calculator to Your Website

Embed this free calculator on a marketing, PPC or analytics resource page. The ?embed=1 view keeps the calculator focused and supports responsive iframe resizing.

Embedding requirement: Keep the SolveIndex attribution and source link visible and unchanged.
  
Marketing - Google Ads & PPC
Understand the metric before using it as a target
Read the detailed guide for the cost per acquisition formula, Target CPA, conversion definitions, CPA vs CAC, benchmarks and practical ways to improve CPA.
Read the Cost Per Acquisition guideBrowse all guides
CPA Calculator Frequently Asked Questions
Enter advertising cost and the conversions or acquisitions counted in the same reporting scope. Target CPA is optional and is used only for the comparison scenario.
It divides advertising cost by the number of conversions or acquisitions you enter. For example, $5,000 of spend divided by 100 conversions produces a $50 average CPA.
Use one clearly defined conversion action or a deliberate group of actions from the same campaign scope. A purchase, qualified lead, signup and booked call can have different economic value, so do not mix them casually.
It calculates the spend allowed for your current conversion count at the entered target and the number of conversions the current spend would support if average CPA matched that target. It is a planning scenario, not a forecast.
Yes. Google Ads can report fractional conversion credit under attribution models, so the calculator accepts positive decimal conversion counts as long as spend and conversions use the same reporting scope.
Use the closest metric for the decision you are making instead of combining every advertising ratio into one number.
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CPA Calculator Disclaimer: Results are planning estimates based on the inputs and definitions you provide. Advertising auctions, attribution, conversion lag, demand, competition, measurement settings and business costs can change actual performance. Use current account data and professional judgment for material budget decisions.