What the CPA Calculator Does
The CPA Calculator works out your Cost Per Acquisition — the average amount you spend to win one customer, lead or conversion from a marketing campaign. It takes two numbers you already have in your ad dashboard and returns a single, clear figure you can use to judge whether a campaign is profitable. CPA is one of the core metrics in digital advertising on platforms like Google Ads, Meta Ads and TikTok, and it works the same way in any currency.
The Inputs You Enter
- Total Ad Spend: the full amount you paid for the campaign over the period you are measuring (for example, the monthly spend on a Google Ads campaign).
- Number of Acquisitions: how many conversions that spend produced — purchases, sign-ups, bookings or whatever you count as a win.
The Formula
The calculation is simply:
$$\text{CPA} = \frac{\text{Total Cost}}{\text{Conversions}}$$
Behind the scenes the tool reads your Total Ad Spend as a decimal and your Number of Acquisitions as a whole number, then divides one by the other. There is one important safeguard: if the number of acquisitions is zero (or blank), the calculator returns a CPA of 0 rather than dividing by zero. You must record at least one acquisition to get a meaningful result.
Worked Example
Suppose you spent 2,000 on a campaign and generated 50 sales:
- $$\text{CPA} = 2{,}000 \div 50 = 40 \text{ per acquisition.}$$
If you compare two campaigns — one at a CPA of 40 and another at 65 — the lower-CPA campaign is acquiring customers more efficiently, assuming the customers are of similar value.
Frequently Asked Questions
What is a good CPA? There is no universal number — a "good" CPA is one that sits comfortably below the lifetime value (or profit margin) of a customer. If each customer earns you 120 in profit, a CPA of 40 is healthy.
Is CPA the same as CPC? No. Cost Per Click (CPC) measures the cost of a single click, while CPA measures the cost of an actual conversion. Many clicks may be needed to produce one acquisition, so CPA is usually higher than CPC.
What currency does it use? The calculator is currency-agnostic. Enter your spend in whatever currency you use, and the CPA result will be in that same currency.
