Customer Acquisition Cost
Aussi : CAC, Cost of Customer Acquisition, Acquisition Cost
Customer Acquisition Cost (CAC) is the total sales and marketing spend divided by the number of new customers gained in a period. It measures how efficiently you grow.
What it is
Customer Acquisition Cost (CAC) is the average amount a business spends to acquire one new paying customer. It is calculated by dividing the total cost of sales and marketing over a period by the number of new customers acquired in that same period.
The basic formula is:
CAC = (Total Sales & Marketing Costs) / (Number of New Customers Acquired)
Costs typically include advertising spend, salaries and commissions for sales and marketing teams, agency fees, software and tooling, and content production. The cleaner and more complete the cost inputs, the more trustworthy the number.
Why it matters
CAC is a core efficiency metric that links spending to growth. It matters because:
- It tells you whether your go-to-market motion is sustainable.
- It is the foundation for unit economics when compared against customer value.
- It guides budget allocation across channels and campaigns.
- Investors and boards use it to judge the health of a growth model.
A low CAC on its own is not the goal. What matters is CAC relative to the revenue and profit a customer generates over time.
How it is used in practice
CAC is rarely viewed alone. Teams pair it with the LTV:CAC ratio (Lifetime Value divided by CAC). A common benchmark is a ratio of 3:1 or higher, meaning each customer returns at least three times their acquisition cost.
Another key companion metric is the CAC payback period: how many months of gross margin it takes to recover the cost of acquiring a customer.
Practical applications include:
- Channel comparison: measuring CAC per channel (paid search, social, events, outbound) to shift budget toward efficient sources.
- Blended vs paid CAC: blended includes organic customers, paid isolates spend-driven acquisition.
- Cohort analysis: tracking CAC trends over quarters to spot rising costs early.
Concrete example
A SaaS company spends $40,000 on marketing and $60,000 on sales in one quarter, totaling $100,000. It acquires 250 new customers.
CAC = $100,000 / 250 = $400 per customer.
If each customer pays $50 per month at 80% gross margin ($40 margin per month), the payback period is $400 / $40 = 10 months. If average customer lifetime is 36 months, lifetime margin is $1,440, giving an LTV:CAC of 3.6:1, a healthy result.