How to calculate CAC
CAC = (advertising spend + other acquisition costs) ÷ new paying customers
Choose one period and one customer definition before you calculate. Add relevant sales and marketing costs such as creative production, acquisition software, agency charges and allocated staff time. Do not count the same cost twice.
The advertising-only figure is useful for comparison, but it is not the complete CAC when other acquisition costs exist. If the customer count includes organic customers, advertising spend divided by that count is not a paid-channel-only CAC.
A worked example
Suppose a creator spends $300 on ads and $100 on other acquisition work in a period, and gains 20 first-time paying customers. Total acquisition cost is $400, so CAC is $20. Advertising spend alone is $15 per new customer. These are illustrative figures, not Rerivo sales data.
What if there are no new customers?
With zero new paying customers, CAC is undefined. A campaign that spends $400 and acquires nobody has not achieved a $0 CAC. The calculator keeps the spending visible and does not divide by zero.
With customers but no recorded acquisition spending, recorded CAC is zero. Check whether time, commissions, software or creative costs were omitted before treating that as a repeatable result.
Compare CAC with contribution
A $20 CAC is neither good nor bad by itself. Compare it with what your first sale retains after fees, refunds, delivery and support costs. For a one-time download, do not assume repeat purchases or lifetime value you have not observed.
Use the break-even ROAS calculator to estimate the acquisition budget left at a stated order volume, or the profit calculator to include your entered CAC in a scenario.
Definition and source
Shopify’s CAC guide explains the acquisition-cost and new-customer definition. The calculator performs the arithmetic on your inputs; it does not verify attribution or supply a universal CAC target.
What this tool does not include
Results cover only the entered costs and assumptions. Tax, financing, exchange rates, unentered support or production costs and the value of your time are excluded. This calculation does not verify market demand or guarantee income.