How to use the customer acquisition cost calculator
Without knowing what one new customer actually costs, there is no way to tell whether to push harder on advertising or pull back. This calculator adds media spend to marketing and sales payroll and divides the total by the customers won in the same period.
Payroll belongs in the numerator. Dividing ad spend alone by new customers always understates CAC. Salaries for the marketing and sales people working on acquisition, agency retainers and content production all count. Costs that go purely to supporting or retaining existing customers do not.
Keep the periods aligned. Pairing this month's spend with last month's signups distorts the result. Adding a lead count also gives you cost per lead and the lead-to-customer conversion rate, which separates a CAC problem caused by expensive traffic from one caused by weak conversion. If new customers exceed leads, the calculator flags the mismatch instead of returning a number.
This is a planning estimate based only on the values entered, excluding taxes and refunds. Written as of September 2026.
Frequently asked questions
Both conventions are used. Counting only paid-channel customers measures ad efficiency, while counting every new customer measures company-wide efficiency. Pick one and keep reporting it the same way.
There is no absolute threshold; it is judged against lifetime value. To see how fast the money comes back, pair it with the CAC payback period and check how many months of gross profit it takes.