Customer Acquisition Cost (CAC)

What is the Customer Acquisition Cost (CAC)?

Customer Acquisition Cost (CAC) is the total amount of money a business spends to acquire a single new customer over a specific period. It includes paid advertising, marketing and sales team salaries, software and analytics tools, agency fees, content production, and any other expense tied directly to attracting and converting leads into paying customers.

CAC is fundamentally about efficiency. It tells you how much you are spending to win each new customer and, when read alongside revenue and lifetime value, whether your acquisition strategy is sustainable.

A related but distinct metric is Cost Per Acquisition (CPA), which can refer to the cost of any action (a lead, a signup, or a free trial), not just a paying customer. CAC counts only the new paying customers.

Why is Customer Acquisition Cost (CAC) important?

Knowing your CAC helps you make better decisions about budgeting, channel mix, and pricing. CAC is most meaningful when compared to lifetime value through the LTV:CAC ratio: a 3:1 ratio is widely considered healthy, below 2:1 is a red flag, and above 5:1 can signal that you are underinvesting in growth.

A second number worth tracking is the CAC payback period: how many months it takes for revenue from a new customer to recover what you spent acquiring them. The shorter the payback, the faster cash returns to the business.

For subscription brands, recurring revenue helps amortize CAC across multiple billing cycles, which is why retention has such a direct impact on whether acquisition spend pays back.

How can you improve CAC?

• Optimize ad spend and audience targeting across channels
• Improve website conversion rates so more of your existing traffic converts
• Use referral and loyalty programs to lower the per-customer cost of acquisition
• Nurture leads more efficiently with email and post-click sequences
• Focus on reducing churn rate and improving retention, so each customer’s lifespan and the LTV side of the ratio both grow

How to calculate Customer Acquisition Cost (CAC)?

Use this simple formula:

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

Example of Customer Acquisition Cost (CAC)

If you spent $5,000 on marketing in a month and acquired 100 new customers, your CAC is $50.

Count only the new paying customers in this period. Returning customers and trial users who have not converted should be excluded so the number reflects acquisition cost, not retention cost. To apply this formula to your own store’s numbers, use the CAC calculator.

Driftcharge Tip

Track CAC alongside LTV every month, not as a one-off. CAC will drift as channels mature, ad costs rise, and your funnel changes, so the goal is not a single number but a steady, healthy ratio. Subscription brands have a structural advantage here, since each renewal stretches the LTV side of that equation a little further.

Ganesh Pawar

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Ganesh Pawar is the founder of Driftcharge, a subscription management app designed to help Shopify merchants streamline and scale their subscription businesses. With a deep focus on solving real-world pain points—like legacy account page support, flexible subscription options, and advanced analytics—Ganesh is passionate about building tools that drive growth and retention.