TL;DR
CAC, customer acquisition cost, is the total sales and marketing spend it takes to acquire one paying customer, calculated by dividing total acquisition spend by the number of new customers won in that period.
What CAC means
A rising CAC without a corresponding rise in customer lifetime value, LTV, is one of the clearest warning signs in a startup's unit economics, since it means growth is getting more expensive to buy over time, not more efficient. Investors typically want to see CAC alongside LTV as a ratio, and alongside payback period, how many months it takes for a customer's revenue to cover what it cost to acquire them.
CAC varies enormously by channel and business model. Paid acquisition through ads tends to carry a visible, easily tracked CAC, while organic or referral-driven growth has a real cost too, it's just harder to attribute directly, and founders sometimes understate CAC by leaving those channel costs out of the calculation entirely.
Why it matters for African founders
With digital ad costs on platforms like Meta and Google largely priced and paid in dollars while much of the customer base transacts in local currency, CAC for African startups can be more volatile than for a comparable company elsewhere. Currency movement alone can shift the real cost of acquisition month to month even if ad spend and customer count stay flat.
Common mistakes founders make with CAC
- Calculating CAC using only paid channel spend and excluding sales salaries, tools and other real acquisition costs
- Comparing CAC across channels without adjusting for each channel's different customer quality and retention
- Not tracking CAC in the currency ad spend is actually billed in
- Presenting CAC without LTV or payback period alongside it, which tells an investor nothing about whether the number is healthy