Calculator: does your marketing turn a profit?
Four required fields. The math almost no company does, and the one that decides whether you can invest more.
Three numbers answer almost everything: what it costs to bring in a customer, what that customer is worth and how long it takes to get the money back. If the second is not at least three times the first, raising the budget raises the problem.
Nothing here is sent anywhere. The calculation runs in your browser and disappears when you close the tab.
Your numbers, in Brazilian reais (R$)
How to read it
What each number means.
CAC
Customer Acquisition Cost. Everything you invested divided by the new customers who arrived. If you spent R$ 8,000 and 20 came, your CAC is R$ 400.
LTV
What a customer is worth. Here the math covers the first year and already applies the margin, on purpose: LTV calculated over a whole lifetime and on gross revenue is the number that makes a company think it can spend what it cannot.
LTV divided by CAC
The ratio. Below 1, you pay to work. Between 1 and 3 it holds up, but leaves no room for error. At 3 or higher, there is room to spend more.
Payback
How many months until you recover what you invested in that customer. It is the number your cash flow feels. A good ratio with a long payback breaks a growing company, because the money goes out today and comes back a year from now.
Frequently asked questions
About the math.
Do my numbers go anywhere?
No. The whole calculation runs in your browser, in JavaScript. No value is sent to any server, and nothing is saved after you close the tab.
There is no form here, on purpose. Asking for an email so someone can see their own number would be charging a toll for a calculation that belongs to them.
Why does LTV only consider the first year?
Because LTV projected over a lifetime is the easiest way to justify a CAC that does not pay for itself. The longer the horizon, the more generous the number and the less useful it is for deciding.
One year is the span most businesses can forecast honestly, and it is the span cash flow can afford to wait.
What if I do not know my margin?
Leave it blank. The calculation assumes 100%, which is the optimistic scenario: as if everything that comes in were profit.
If the result is already bad at a 100% margin, it is worse in real life. That alone is a diagnostic.
Does the 3x ratio apply to every business?
It is a reference, not a law. A business with recurring revenue and high retention does fine with less. A one-time-purchase business with a short cycle needs more.
What does not change is the direction: below 1 there is no case where raising the budget improves anything.
Does the calculator replace a diagnostic?
No. It shows whether the math works. The diagnostic answers why it does not work and what to do, in what order, looking at channel, offer, funnel and what has already been tried.
But showing up to a conversation with CAC, LTV and payback in hand gets you halfway there.
After the math
The number shows. The diagnostic explains.
If the math did not work, the reason is somewhere between offer, channel and funnel. That is what the diagnostic looks for.