CAC is your most important unit economic
Customer acquisition cost tells you how much you spend to gain each new customer. It determines whether your business model is sustainable, how fast you can grow, and where to invest your next dollar.
Most businesses either do not track CAC or calculate it incorrectly. Getting this number right changes how you make decisions.
The basic formula
CAC = Total Sales and Marketing Costs / Number of New Customers Acquired
For a given period (usually monthly or quarterly), add up everything you spent on acquiring customers and divide by the number of new customers you gained.
What to include in the numerator
Marketing spend. Advertising, content creation, events, sponsorships, marketing tools, and agency fees.
Sales costs. Commission payments to agents, salaries for any in house sales staff, CRM and sales tools, training costs, and platform fees (like Zepys).
Overhead allocation. A reasonable portion of management time spent on sales and marketing activities.
Do not include product development, customer support for existing customers, or general business overhead. You want to isolate the cost of acquisition specifically.
Calculating CAC by channel
Total CAC is useful but channel specific CAC is more actionable. Calculate separately for:
Paid advertising: Ad spend / customers from paid ads Commission agents: Total commissions and platform fees / customers from agents Content marketing: Content creation costs / customers from organic search Referrals: Referral incentive costs / customers from referrals
This reveals which channels are most efficient and where to increase or decrease investment.
CAC payback period
How long does it take for a new customer to generate enough gross profit to cover their acquisition cost? If your CAC is $500 and each customer generates $100 per month in gross profit, your payback period is 5 months.
Payback periods under 12 months are generally healthy. Over 18 months is a warning sign unless your retention is exceptionally strong.
CAC to LTV ratio
The ratio of customer lifetime value to acquisition cost tells you the efficiency of your growth model. A healthy ratio is 3:1 or higher, meaning each customer generates at least three times what they cost to acquire.
Below 1:1 means you are losing money on every customer. Between 1:1 and 3:1 suggests room for improvement. Above 5:1 might mean you are underinvesting in growth and could acquire customers more aggressively.
Common mistakes
Ignoring time. A customer acquired by a salaried salesperson over three months absorbed three months of salary cost, not just the commission on the deal.
Cherry picking costs. Including only direct advertising spend and ignoring sales team costs understates your true CAC.
Mixing customer types. If you serve enterprise and SMB customers, calculate CAC separately. They have very different costs and values.
The bottom line
Accurate CAC measurement is the foundation of smart growth decisions. Include all acquisition costs, calculate by channel, track your payback period, and monitor your CAC to LTV ratio. These numbers tell you whether your growth is sustainable and where to invest next.