Free CPA Calculator: Cost Per Acquisition and Target Budget
CPA is the cost of one chosen conversion. Calculate it from spend and conversions, or work backwards from a target CPA to estimate the budget or conversion volume required for a campaign.
CPA measures the cost of a chosen conversion. Define the conversion event and reporting period before comparing campaigns; customer acquisition cost can be broader because it may include non-media sales and marketing costs.
How this free tool works
Calculate cost per acquisition, required ad spend or conversions from a target CPA. Free, browser-first and useful for paid search, paid social and lead campaigns. The result is designed to be transparent: you can see the inputs, the formula and the assumptions instead of receiving a black-box score.
CPA = total ad spend ÷ conversions. Required spend = target CPA × planned conversions. Required conversions = ad spend ÷ target CPA.
Best for
- Media buyers setting a target cost per lead or purchase
- Founders translating a conversion goal into a test budget
- Teams separating a campaign CPA from fully loaded customer acquisition cost
Frequently asked questions
What is the CPA formula?+
CPA equals total advertising spend divided by the number of completed conversions in the same scope and reporting period.
Is CPA the same as CAC?+
Not always. CPA can describe any conversion, such as a lead or purchase, while CAC usually means the broader cost to acquire a new customer and may include sales and non-media costs.
How much should I spend to get more conversions?+
For a simple planning estimate, multiply your target CPA by the number of conversions you want. Actual delivery depends on auction, audience, creative, conversion rate and tracking quality.
References and methodology
We use primary documentation where available and treat calculators as planning aids, not guarantees. Check the linked source when a platform changes its rules.
- Google Ads Help: About cost per conversion
Official Google Ads definition and reporting context for cost per conversion.
- Google Ads Help: About conversion tracking
Use a clearly defined conversion action before comparing CPA across campaigns.
Turn this answer into a repeatable growth workflow.
Use the free result as your starting point, then move the next campaign, creative or growth decision into GrowthGPT when the work becomes repetitive.