Glossary
CAC: what it is, the formula, and how it differs from CPA
Customer acquisition cost counts everything it took to win a customer. The formula, which costs to include, and how to tell whether yours is healthy.
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CAC is customer acquisition cost: what it actually cost you to win one new customer. It is the number the business owner cares about, not the one the ad platform shows. Add up everything spent on acquiring, then divide by the new customers in that period.
Formula
CAC = (media spend + salaries + tools + commissions) ÷ new customers.
Say you spent US$ 6,000 on ads and US$ 4,000 on the people running those campaigns, and closed 50 new customers. Your CAC was US$ 200. The platform was probably showing a cost per conversion far below that, and neither number is wrong — they measure different things.
CAC versus CPA: the expensive mix-up
| Metric | What it includes | Who uses it |
|---|---|---|
| CPA | Ad spend on that platform | Whoever runs the campaigns |
| CAC | Media across channels, team, tools | Whoever sets the budget |
A team can celebrate an excellent CPA while the company's CAC gets worse, because headcount grew or other channels got expensive. That is why a client report needs both numbers, with the difference explained once, at the start of the relationship.
What counts as a good number
CAC is never judged alone. It is judged against two things:
- What the customer is worth over the relationship. If your average customer brings in US$ 1,200 and your CAC is US$ 200, there is room. If they bring in US$ 250, there is not.
- How long it takes to earn back. A CAC that looks healthy on paper can still break your cash flow if it takes fourteen months to recover.
What quietly pushes CAC up
- Cheap channels saturate and the mix shifts toward expensive ones.
- Sales close rate drops, so each sale needs more leads.
- Tools accumulate and nobody audits the list.
- Repeat buyers get counted as new customers.
That last one is the most common, and the most flattering. Define "new customer" before you calculate, and do not change the definition between months.
To build the whole picture, carry on with conversion rate and ROAS, and see the pricing if you want spend from all three channels in one place.
Frequently asked questions
Is CAC the same as CPA?
No. CPA usually counts only ad spend on one platform. CAC counts everything it took to acquire the customer: media across all channels, salaries, tools and commissions.
Which costs belong in CAC?
Ad spend, the salaries of the marketing and sales people involved, software, and sales commissions. Divide that total by the new customers from the same period.
What counts as a good CAC?
One you recover inside the window your cash flow can survive, and that sits well below what the customer is worth over the whole relationship.