Customer Acquisition Cost (CAC) represents the total expense a company incurs to acquire a single new customer, calculated by dividing all sales and marketing costs by the number of customers gained during a specific period. This metric includes advertising spend, salaries of marketing and sales teams, software tools, creative production, and any other resources dedicated to converting prospects into paying customers.
CAC varies significantly across industries and business models. A B2B SaaS company might spend $5,000 to acquire an enterprise customer, while a consumer mobile app could acquire users for $2-3 each. The calculation seems straightforward, but investors should verify which costs founders include. Some entrepreneurs exclude overhead or employee benefits, artificially lowering their CAC and painting an unrealistic picture of unit economics.
Why It Matters
CAC determines whether a business model can scale profitably. Investors compare CAC to Customer Lifetime Value (LTV) using the LTV:CAC ratio, with healthy businesses typically showing a 3:1 ratio or better. A company spending $300 to acquire a customer who generates $250 in lifetime profit will burn through capital and fail, regardless of how fast it grows. Understanding CAC trends over time reveals whether a company is improving its marketing efficiency or facing rising competition that drives up acquisition costs. Startups with rising CAC often signal market saturation or poor product-market fit.
Example
A subscription meal kit service spends $200,000 on Facebook ads, $150,000 on influencer partnerships, and $100,000 in sales team salaries during Q1. The company also spends $50,000 on marketing software and analytics tools. This totals $500,000 in acquisition costs. During the same quarter, they acquire 2,500 new customers. Their CAC is $500,000 ÷ 2,500 = $200 per customer. If their average customer stays subscribed for 18 months at $50 monthly profit, the LTV is $900, yielding a healthy 4.5:1 ratio. However, if customer retention drops and the average subscription length falls to 6 months, LTV drops to $300, creating a barely sustainable 1.5:1 ratio that would concern most investors.