What Is Customer Acquisition Cost (CAC)?

What customer acquisition cost means in plain words

Customers rarely arrive for free. You pay for ads, hand out samples, attend events or spend hours on calls. CAC adds all of that up and spreads it over the customers you won, giving you the price of one new customer.

It is one half of your unit economics, the profit or loss on a single customer. The other half is customer lifetime value, the gross profit that customer brings over time.

How to calculate CAC

Include these costs:

• Advertising and sponsored posts
• Marketing and sales software
• Agencies, freelancers and commissions
• Free trials, samples and first-order discounts
• Pay for anyone whose job is sales or marketing, including a share of your own if you want the true figure

Two versions are useful. Blended CAC divides all spend by all new customers, including those who came through word of mouth. Paid CAC divides spend by only the customers who came from paid channels. Paid CAC tells you what the next customer will cost if you spend more. You can run both in the CAC calculator.

A worked example

These are made-up numbers. Say you sell a meal-prep subscription and in one month you spend the following.

You win 60 new customers that month, so blended CAC is $3,000 / 60 = $50. Of those 60, 20 were referred by friends and cost you nothing. The other 40 came from ads, so paid CAC is $3,000 / 40 = $75. If you double the ad budget, expect new customers to cost closer to $75 than $50.

Why it matters and when you meet it

CAC tells you whether growth makes money or loses it. If a customer costs more to win than they return in gross profit, each sale makes the business poorer, and faster growth only raises the amount of cash you lose each month. It also shows how long your cash is tied up, which you can check with the CAC payback period calculator.

You first meet CAC when you plan how to reach customers, in the marketing and financial chapters of a business plan. At that stage it is an estimate, so write down the guesses behind it. It becomes real once you start selling. Your first 10 customers usually come from personal outreach, which costs time more than money, so do not expect that early figure to hold as you grow. In Fonda, this work sits in the Scale phase, under GTM and Key metrics.

Common mistakes

• Counting only ad spend. Tools, freelancers, discounts and salaries are part of the cost.
• Counting leads or sign-ups as customers. Divide by people who paid.
• Mismatched periods. If a sale takes two months to close, this month's customers came from earlier spend.
• Relying on the blended figure. Free referrals make paid channels look cheaper than they are.
• Assuming it stays flat. The easiest customers come first, so CAC often rises as you reach further.

Related terms

• Customer lifetime value: what one customer is worth, the number to compare CAC against.
• Churn rate: how fast customers leave, which decides how long you have to earn CAC back.
• Go-to-market strategy: the plan for which channels you use to win customers.