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Performance guide

How to calculate CAC

Learn the CAC formula, how customer acquisition cost differs from CPA, and how to interpret CAC with better unit-economics context.

CAC stands for customer acquisition cost. It measures how much it costs to acquire one new customer across the spend and customer scope you choose.

It is one of the most useful acquisition metrics because it connects marketing spend to actual customer growth rather than only to clicks or leads.

CAC formula

CAC = Marketing Spend / New Customers

Use total marketing or acquisition spend and the number of new customers from the same scope and time window.

The exact CAC definition can vary by team, which is why it is important to keep cost inputs and customer definitions consistent.

How to calculate CAC correctly

  1. 1Decide which costs belong in CAC before doing the calculation.
  2. 2Count the number of new customers acquired during the same reporting window.
  3. 3Divide spend by new customers to get average acquisition cost per customer.
  4. 4Review CAC together with LTV:CAC, payback period, and lead-to-customer conversion where relevant.

Worked example: CAC from spend and new customers

  • Marketing spend: $6,000
  • New customers: 60
  • CAC = 6,000 / 60 = $100

The result is $100 CAC. That means each new customer cost one hundred dollars to acquire on average during that period.

How to interpret CAC in practice

  • Lower CAC is usually better, but only when customer quality and downstream value still hold up.
  • CAC is more meaningful when reviewed with customer value, not by itself.
  • A stable CPA can still hide worsening CAC if fewer leads turn into actual customers.

FAQ

Should CAC include agency fees or salaries?+

That depends on how your team defines CAC, but the key is consistency. If you include broader acquisition costs, keep that definition stable across comparisons.

How is CAC different from CPA?+

CAC usually refers to the cost of acquiring a customer, while CPA can refer to the cost of any defined acquisition event such as a lead, signup, or purchase.

What makes CAC useful beyond media optimization?+

It connects marketing efficiency to real customer growth and becomes much more powerful when paired with LTV:CAC and payback period.