Customer Acquisition Cost Calculator

Customer acquisition cost divides everything you spent to win demand by the number of customers who actually paid. The arithmetic is trivial; the judgement sits in deciding which costs belong in the numerator and which signups belong in the denominator.

Marketing spend for the periodAd spend, content, events — everything under marketing.Sales spend for the periodSales salaries, commission and tooling. Leaving this out is the classic undercount.New customers won in the periodPaying customers who actually converted, not signups or trials.Revenue per customer per monthAverage monthly revenue from one customer.Gross margin(%)What is left of that revenue after the cost of serving the customer.

Customer acquisition cost

320

Total sales and marketing spend: 80,000
CAC counting marketing spend only (the undercount): 200
Months to pay the CAC back: 5.3333
Customers won per 1000 of spend: 3.125

Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.

The formula this calculator uses

CAC = (Marketing spend + Sales spend) / New paying customers

Marketing spend: Ad spend, content, events and every other demand-generation cost for the period
Sales spend: Sales salaries, commission and tooling — the half most teams leave out
New customers: Customers who converted and paid, not signups, trials or leads
CAC: Average cost of winning one paying customer

How to check the result by hand

1
Fix the period before anything else
Choose a window — a month or a quarter — and commit to it for both numerator and denominator. Spend and conversions rarely land in the same week, so a period that is too short produces noise rather than signal. Write the window next to the figure whenever you quote it, because a monthly CAC and a quarterly CAC for the same business are not the same measurement.
2
Total marketing spend for that period
Paid media, content, events, tools and agency fees: everything under the marketing budget. In the reference case this is 50000. Do not silently exclude brand work because it is hard to attribute, and do not subtract any discount a vendor gave you after the period closed.
3
Add sales spend, including salaries and commission
Sales is the half that goes missing, and leaving it out understated our reference case by 120 per customer: 50000 alone gives 200, while 50000 plus 30000 gives the honest 320. Count the whole cost of the selling function for the period, including the portion of management time spent closing deals, and do not net out commission that has not yet been invoiced.
4
Count only customers who converted and paid
Trials, signups and demo requests belong to the funnel, not to this denominator. Here the period produced 250 paying customers, so 80000 divided by 250 gives a CAC of 320. If some of those customers arrived through referrals or organic search, leave them in for the blended figure and compute a separate paid-only number before judging any campaign.
5
Put the CAC next to payback and lifetime value
Contribution per customer is 80 x 0.75 = 60 a month, so payback is 320 / 60 = 5.33 months. Over a 30-month life that contribution becomes 1800, a ratio of 5.63 to the CAC. Report all three together and the number stops being a headline you defend and becomes a set of constraints you can act on.

For worked examples, common mistakes and the limits of this formula, read the full How To Calculate Customer Acquisition Cost page.