CAC (Customer Acquisition Cost)

In one line

CAC (Customer Acquisition Cost) is the cost of acquiring one customer: total acquisition spend ÷ customers acquired.

Why it matters

What matters more than the CAC number itself is what you count as a "customer." Install-based, signup-based, and paying-user-based CAC can differ enormously — define it consistently across your team so channels and periods are actually comparable. Counting paying users is usually the most meaningful choice.

Go deeper

How CAC pairs with LTV to guide channel decisions is covered in LTV:CAC Ratio.