Customer Acquisition Cost (CAC)
What you paid to acquire one customer
How much total marketing and ad money you spent to acquire one brand-new paying customer.
Why It Is Critical
Performance marketing is, at its core, a CAC business. Every bid you place, every budget decision you make, every campaign you scale or kill - all of it is ultimately a CAC decision wearing a different costume. If you don't know your CAC, you don't know whether your marketing is making money or destroying it.
How It Works & Underlying Dynamics
CAC is calculated by dividing everything you spent to acquire customers - ad spend, agency fees, tool costs, sales team costs - by the number of new customers that spend produced. The most important word in that sentence is 'new'. CAC should only count first-time customers, not repeat buyers. Including repeat buyers artificially deflates your CAC and makes acquisition look cheaper than it is.
Strategic Rules of Thumb & Execution Playbook
- Calculate CAC per channel and per campaign - never rely on a single blended number.
- A blended CAC hides which channels are efficient and which ones are quietly bleeding money.
- Set a maximum affordable CAC ceiling before you scale any campaign. If actual CAC exceeds it, pause before you spend more.
- Recheck CAC monthly. A campaign that looked efficient at ₹600 CAC in Month 1 can drift to ₹1,100 by Month 3 as audience saturation sets in.
Calculation Example & Benchmark Matrix
| Input Metric | Result Calculation |
|---|---|
| Total Ad Spend: ₹1,00,000 | New Customers: 125 |
| Formula: ₹1,00,000 ÷ 125 | CAC = ₹800 per customer |
'My maximum affordable CAC is the ceiling, not a suggestion. If a channel is sitting at ₹1,200 and my ceiling is ₹800, I do not keep running it because the reach numbers look impressive. Reach does not pay salaries.'