Customer Acquisition Cost (CAC)

Customer Acquisition Cost (CAC) is the total amount of money your startup spends to acquire a single paying customer. It includes all marketing, sales, and related costs necessary to turn a prospect into a customer.

CAC is a core metric for startups because it shows how much you need to spend to grow your user base sustainably. If your CAC is higher than what a customer brings in (Unit Revenue or LTV), your startup is losing money on growth.

🧩 What is CAC?

CAC = Total Sales & Marketing Costs ÷ Number of New Customers Acquired

It answers the question: “How much does it cost to get one customer?”

Costs included in CAC:

  • Advertising spend (paid ads, social, search, etc.)
  • Sales team salaries and commissions
  • Marketing team salaries
  • Content, campaigns, and creative production costs
  • Tools and software for acquisition (CRM, email platforms, analytics)
---

🧠 Why CAC Matters (Especially for Startups)

Knowing CAC helps you answer essential questions for early-stage growth:

  • Can we acquire customers profitably?
  • Is our marketing and sales efficient?
  • How much should we invest to scale?
  • Are we spending too much on channels that don’t convert?

Tracking CAC over time allows founders to optimize channels, budgets, and processes to improve unit economics.

📘 How to Calculate CAC

Simple formula:

CAC = Total Sales & Marketing Spend ÷ Number of New Paying Customers

Example:

  • Total marketing spend = $5,000
  • Total sales expenses = $2,000
  • Total new customers acquired = 100
  • CAC = ($5,000 + $2,000) ÷ 100 = $70 per customer

📈 What Counts as Acquisition Cost

  • All expenses to convert a prospect to a paying customer
  • Advertising, campaigns, sales team, marketing tools
  • Campaign production costs

Exclude costs unrelated to acquisition, such as product development or general overhead — they belong to unit costs or fixed expenses.

💡 Common Mistakes Founders Make

  • Counting total revenue instead of new customers
  • Mixing CAC with churned customers
  • Ignoring multi-step sales processes
  • Including costs unrelated to customer acquisition
  • Not calculating CAC per channel

⭐ Practical Examples

Example 1: SaaS Startup
Marketing spend = $3,000
Sales salaries = $1,500
New customers = 100
CAC = $45 per customer

Example 2: E-commerce
Ad spend = $1,000
Creative production = $200
New paying customers = 50
CAC = $24 per customer

Example 3: Mobile App
Ads = $500
App store optimization = $100
New installs that convert = 60
CAC = $10 per customer

🎯 Startup Rule (Remember This)

CAC must always be lower than your Unit Revenue or LTV to ensure sustainable growth.
Tracking CAC per channel and campaign helps you scale efficiently without burning money.