Customer Acquisition Cost (CAC) Calculator
The true cost to acquire a paying customer — and why it isn't your CPA.
Customer acquisition cost (CAC) is ad spend divided by new customers — the cost to win one paying buyer. It is not CPA, which divides by actions like clicks or leads. $10,000 and 160 customers is a $62.50 CAC; if those came from 200 tracked actions, CPA is only $50. Enter your numbers to see CAC, CPA, and your max sustainable CAC.
These calculators are for planning and estimation, not accounting or financial advice. Verify against your actual platform, payment-processor, and bookkeeping figures before making budget or pricing decisions.
Customer acquisition cost (CAC)
$62.50
Your max sustainable first-order CAC is $49.03 — this is above your first-order margin.
About the CAC Calculator
Customer acquisition cost is the amount you spend to turn a stranger into a paying customer: total acquisition spend divided by the number of new customers it produced. It sounds simple, and it gets sabotaged by a lookalike metric — CPA, cost per action. CPA divides spend by actions, and an action is whatever the pixel counts: a click, a lead, an add-to-cart, a conversion event. Those are not customers. If $10,000 in spend generates 200 tracked actions but only 160 of them become paying customers, your CPA reads a flattering $50 while your true CAC is $62.50. Optimizing campaigns to CPA makes the dashboard look efficient while the number that actually has to stay below your margins drifts higher. CAC only means something next to two other figures. The first is your contribution margin per order — your maximum sustainable first-order CAC — because if it costs more to acquire a customer than one order profits, you need repeat purchases just to break even. The second is lifetime value: with real repeat business you can afford a CAC well above one order's margin, up to a healthy fraction of lifetime contribution. This tool shows CAC, CPA, and the gap between them, then sets CAC against your max sustainable first-order CAC so you can see immediately whether acquisition is paying for itself.
Frequently asked questions
What is the difference between CAC and CPA?+
CAC is cost per paying customer (spend ÷ new customers). CPA is cost per action (spend ÷ clicks, leads, or conversion events). Because not every action becomes a customer, CPA is usually lower than CAC — and optimizing to CPA can hide a rising CAC.
How do I calculate customer acquisition cost?+
Divide your acquisition spend by the number of new customers it produced in the same period. $10,000 in ad spend that wins 160 new customers is a CAC of $62.50. For a fuller picture, include creative and agency costs in the spend, not just media.
What is a good CAC?+
A good CAC is one comfortably below the profit a customer generates. On the first order, keep CAC under your contribution margin per order. If customers reorder, you can go higher — up to a target fraction of lifetime value, often a 3:1 LTV:CAC ratio.
Why is my CAC higher than my CPA?+
Because actions outnumber customers. Clicks, leads, and add-to-carts all count as actions, but only some convert to paying buyers. The more actions per customer, the wider the gap — which is exactly why CAC, not CPA, is the number to manage to.
By D.J. Gelner
D.J. Gelner is a direct-response marketer with 12+ years running growth for DTC and supplement brands, including VP-level roles. A former attorney, he builds and verifies the unit-economics math behind paid-media decisions daily.