Customer Acquisition Cost Calculator
What it costs to win one customer — and how long they take to pay it back.
CAC is total sales and marketing spend divided by the customers that spend won.
How the customer acquisition cost calculator works
CAC is total sales and marketing spend divided by the customers that spend won. The arithmetic is trivial; the judgement is in what goes into the numerator.
Fully loaded CAC includes salaries, commissions, tools and overhead as well as advertising. Paid CAC counts only media spend. The two can differ by a factor of three, so a CAC quoted without saying which it is means nothing. This page computes both.
The number that actually matters is payback: how many months of gross profit it takes to recover the acquisition cost. Under twelve months is generally healthy for a subscription business; beyond eighteen, growth consumes cash faster than it produces it.
Formula: CAC = (sales + marketing spend) / new customers
Worked examples
| Inputs | Fully loaded CAC | Note |
|---|---|---|
| 100,000 spend winning 250 customers | $400.00 | CAC 400, payback about 4.4 months |
| Marketing spend only | $160.00 | CAC 160 |
| A long payback | $1,000.00 | over 27 months |
FAQFrequently asked questions
How do I calculate customer acquisition cost?
Divide everything you spent winning customers by the number you won. What counts as "everything" is the judgement call.
Should CAC include salaries?
Fully loaded CAC does, and it is the more honest figure. Marketing-only CAC is useful for comparing channels, not for judging the business.
What is a good CAC?
There is no absolute answer — it only means something against what a customer is worth. Payback period and the LTV:CAC ratio are the tests.
What is a good payback period?
Under twelve months is the usual benchmark for subscription businesses. Beyond eighteen, growth consumes cash faster than it generates it.
Why use gross profit rather than revenue for payback?
Because the cost of serving the customer is not available to repay acquisition. Using revenue flatters the number.
Where these figures come from
- Corporate Finance Institute — EBITDA — why EBITDA is a non-GAAP measure with no single definition
- US SEC — Non-GAAP Financial Measures, Compliance & Disclosure Interpretations — the disclosure rules that exist precisely because EBITDA is not standardised
- Australian Securities and Investments Commission — the Australian corporate regulator
Last checked: September 2026. These are standard management-accounting definitions; where a term has no single agreed definition, the page says so.