Customer Acquisition Cost (CAC)
Customer Acquisition Cost (CAC) is the total sales and marketing spend required to win one new customer.
Also known as: CAC
How CAC is calculated
The standard formula for Customer Acquisition Cost is simple: take all the money spent on sales and marketing over a defined period, then divide it by the number of new customers acquired in that same period. If a company spends 100,000 in a quarter and signs 50 new customers, its CAC is 2,000.
The important detail is what you include in the numerator. A basic version counts only direct advertising and campaign spend. A fully loaded version adds sales and marketing salaries, commissions, software and tooling, agency fees, and a share of overhead. Fully loaded CAC gives a truer picture of what acquisition actually costs, which is why finance and leadership teams tend to prefer it.
- Numerator: total sales and marketing costs in the period.
- Denominator: number of new customers acquired in the period.
- Fully loaded CAC includes people, tools, and overhead, not just ad spend.
- Match the time periods so spend and new customers align.
Why CAC matters in B2B
In B2B, sales cycles are long and deals are large, so acquisition is expensive. Knowing your CAC tells you whether your go-to-market motion is efficient and whether you can afford to grow. It is a core input for budgeting, forecasting, and deciding which channels and segments deserve more investment.
CAC rarely stands alone. Its real power comes from comparison. Teams look at CAC alongside customer lifetime value, average deal size, and how long it takes to recover the acquisition cost. A CAC number in isolation cannot tell you if it is good or bad without knowing what a customer is worth.
- Helps set realistic sales and marketing budgets.
- Reveals which channels and segments acquire customers most efficiently.
- Informs pricing and revenue targets.
- Signals whether growth is sustainable or burning cash.
How CAC relates to neighbouring terms
CAC is one half of the most watched efficiency metric in subscription and SaaS businesses: the LTV:CAC ratio. LTV, or lifetime value, estimates the total revenue or profit a customer generates over their relationship with you. A healthy ratio means each customer returns meaningfully more than they cost to win; a ratio near or below one signals you are losing money on acquisition.
Another closely linked concept is the CAC payback period, which measures how many months of revenue it takes to earn back the cost of acquiring a customer. CAC also connects to metrics like conversion rate, average deal size, and churn, because anything that changes how many customers you win, how much they pay, or how long they stay will change the economics around your CAC.
- LTV:CAC ratio compares customer value to acquisition cost.
- CAC payback period measures how long it takes to recover the cost.
- Churn erodes the value side of the equation and worsens CAC economics.
- Conversion rate and deal size directly affect CAC.
Common mistakes with CAC
The most frequent error is under-counting costs. Teams report only ad spend and ignore salaries, commissions, and tools, producing a flattering but misleading number. Another mistake is mismatching time frames, such as comparing this quarter's spend against customers who were actually won by campaigns from earlier periods with long sales cycles.
People also treat a lower CAC as automatically good. Cutting spend can reduce CAC while also starving the pipeline and slowing growth. And blending all customers together hides the fact that CAC varies widely by channel, segment, and product. Segmenting CAC usually reveals where money is well spent and where it is wasted.
- Leaving salaries and overhead out of the calculation.
- Mismatching spend periods with acquisition periods.
- Assuming lower CAC is always better regardless of growth impact.
- Reporting one blended CAC instead of segmenting by channel or customer type.
Frequently asked questions
What is a good CAC?
There is no universal good number because it depends entirely on what a customer is worth. The common benchmark is the LTV:CAC ratio, where roughly three to one is often considered healthy, meaning a customer returns about three times what they cost to acquire.
What is the difference between CAC and CPA?
CPA, or cost per acquisition, often refers to the cost of a single action or conversion like a lead or signup, while CAC specifically measures the cost of winning a paying customer. CAC is broader and typically includes sales costs, not just marketing spend.
Should CAC include sales team salaries?
For an accurate picture, yes. A fully loaded CAC includes sales and marketing salaries, commissions, tools, and overhead. Excluding them can dramatically understate the true cost of acquiring a customer, especially in B2B where sales headcount is a major expense.