Free tools / CAC payback calculator
Free toolCAC payback calculator
How long before a new customer has paid back what you spent winning them? This is the cash question hiding behind every growth metric, and it is the one that decides whether you can afford to grow faster.
Your numbers
Nothing you type here is stored.
Your payback period will appear here
Enter your acquisition cost, revenue per customer and margin, then press Calculate.
What would shorten it
Payback tells you about cash. For whether the customer is worth it at all, see the LTV to CAC calculator.
How this works
The formula
Payback months = acquisition cost ÷ monthly gross profit
Spend 120,000 winning a customer who leaves you 30,000 of gross profit a month, and you are square after four months. Everything after that is yours, as long as they stay.
Why this beats the ratio for cash
LTV to CAC tells you whether a customer is worth winning. Payback tells you when you get your money back. You can have an excellent ratio and still run out of cash waiting, which is how fast-growing businesses die.
What this does and does not tell you
- It assumes the customer stays that long. If your payback is longer than your average customer lifetime, customers never pay for themselves at all.
- It uses gross profit, not revenue. Recovering cost out of revenue you have already spent delivering is not recovery.
- It assumes you are paid monthly and on time. Annual contracts paid up front pay back far faster than the same revenue collected monthly.
- It ignores the overheads that keep running while you wait.
- Faster payback lets you recycle the same cash into winning the next customer, which compounds. That is why the number matters more than it looks.
Questions people ask
Under twelve months is widely treated as comfortable, and under six as strong, but the honest answer depends on your cash. If you have deep funding you can wait longer. If you are funding growth from your own revenue, a long payback caps how fast you can grow no matter how good your ratio looks, because every new customer ties up cash you cannot use again for months.
Because the two answer different questions. The ratio asks whether a customer is worth more than they cost. Payback asks when you actually get the money. A business with a 5x ratio and eighteen month payback is spending real cash today against profit that arrives a year and a half later. That gap has to be funded from somewhere, and running out while technically profitable is one of the most common ways growing businesses fail.
Three levers. Raise the price, improve the gross margin, or lower acquisition cost. There is also a fourth that people forget: change how you bill. Moving customers from monthly to annual upfront payment can turn a twelve month payback into an immediate one without changing a single underlying number, because payback is about cash timing rather than profitability.
Gross profit, always. If a customer pays you 50,000 a month and it costs 20,000 to serve them, only 30,000 is available to pay back what you spent acquiring them. Using revenue makes your payback look almost twice as fast as it really is, which is a comfortable mistake to make and an expensive one to act on.
Growth you cannot fund is not growth.
We help businesses see the cash behind the metrics, before it becomes a problem. Start with a free health check.
Get your free health check