What is CAC?
Customer Acquisition Cost (CAC) measures how much your business spends to win each new customer. It includes every cost associated with marketing and sales: ad budgets, team salaries, software subscriptions, agency fees, content production, and any other expense that contributes to generating new business.
CAC is a vital health metric. If it costs you more to acquire a customer than that customer is worth, the business loses money on every sale. Tracking CAC over time reveals whether your growth is efficient and sustainable or whether rising costs are eroding margins.
Why CAC matters
CAC determines how fast you can grow and how much you can afford to invest in acquisition. It is inseparable from customer lifetime value (LTV). The ratio of LTV to CAC is one of the most important numbers in business: a 3:1 or higher LTV:CAC ratio generally signals healthy unit economics.
Rising CAC is one of the earliest warning signs of a struggling growth engine. It can signal market saturation, creative fatigue, increased competition, or inefficient operations -- and the sooner you spot the trend, the sooner you can correct it.
Investors, board members, and leadership teams all watch CAC closely. It is often the deciding factor in whether a company scales aggressively or pumps the brakes.