CAC — Customer Acquisition Cost
CAC is the total cost to acquire a new customer, including all sales and marketing spend. A core unit economics metric for evaluating business viability.
What Is CAC?
Customer Acquisition Cost (CAC) is the total cost your company incurs to acquire one new paying customer. It’s calculated by dividing total sales and marketing spend by the number of new customers acquired in the same period.
CAC = Total Sales & Marketing Spend ÷ New Customers Acquired
If you spend $10,000 on marketing in a month and acquire 50 customers, your CAC is $200.
What Goes Into CAC?
CAC should include all costs related to acquiring customers:
- Advertising spend (paid search, social, display)
- Salaries and commissions for sales and marketing staff
- Marketing software (CRM, automation, analytics tools)
- Events, content creation, PR
- Agency fees
Two versions are commonly used:
- Blended CAC: All acquisition costs ÷ all new customers (organic + paid)
- Paid CAC: Paid channel costs ÷ new customers from paid channels only
Tracking both gives you a clearer picture of channel efficiency.
The CAC : LTV Ratio
CAC is most meaningful when compared to Lifetime Value (LTV):
| Ratio | Interpretation |
|---|---|
| LTV : CAC < 1 | Losing money on every customer — unsustainable |
| LTV : CAC = 1–2 | Breaking even or marginal — needs improvement |
| LTV : CAC = 3 | Healthy benchmark for most SaaS businesses |
| LTV : CAC > 5 | Possibly underinvesting in growth |
A ratio of 3:1 is the widely cited benchmark for a sustainable B2B SaaS business.
CAC Payback Period
Another key metric derived from CAC:
Payback Period = CAC ÷ Monthly Gross Profit per Customer
If CAC is $600 and a customer generates $100/month in gross profit, payback is 6 months. Most SaaS businesses target under 12 months; best-in-class companies achieve 6 months or less.
How to Reduce CAC
- Improve conversion rates at each funnel stage
- Invest in content marketing — organic traffic has near-zero marginal CAC
- Build referral and word-of-mouth loops — the lowest-cost channel
- Narrow your ICP — targeting precisely reduces wasted spend
- Shorten sales cycles — faster closes reduce sales team costs per deal
Common Mistakes
- Forgetting overhead — headcount is often 60–70% of CAC; don’t leave it out
- Mixing time periods — spend and customer acquisition must be measured in the same window
- Ignoring churn — a low CAC means nothing if customers leave after two months
- Over-optimizing too early — in early stages, learning which channels work matters more than CAC
Key Takeaway
CAC is a lagging indicator of your go-to-market efficiency. Benchmark it against LTV to understand whether your business model is fundamentally sound, and track it over time to ensure unit economics improve as you scale.