Customer Acquisition Payback Calculator

Four thousand a month brings in twenty-five customers, so each one costs a hundred and sixty. At thirty-eight dollars of margin a month they pay back in month five.

But the business does not come back to level until month nine, and it is seven thousand dollars down before it turns.

Those are two different questions and usually only the first one gets asked. One group of customers turns profitable on one date. A business that keeps acquiring is paying for the next group before the last group has paid back, so cash keeps falling well after the cohort maths says everything is fine. The depth of that trough is the working capital the growth needs, and businesses find it out by running out of money in a month when every other figure looked healthy.

The page shows both, month by month, with the deepest point and the recovery marked.

It also does the payback properly, which means with churn in it. Cost divided by monthly margin assumes every customer is still there, and the ones who leave stop paying — so the usual sum is always optimistic, and sometimes it is not merely optimistic but wrong in kind. Above a certain rate of leaving, a customer’s total worth has a ceiling that sits below what they cost, and no number of months closes the gap. The page says never, and says why, where the division would have returned a cheerful four.

There is no ratio graded anywhere on it. The value-to-cost figure is on the compare screen because it is arithmetic, but nothing here will tell you what it ought to be. Three to one has no source anybody can point at and varies by an order of magnitude between a business with no marginal costs and one that ships boxes.

Churn is taken as steady, and yours will not be. In most businesses it is highest in the first month or two and settles afterwards. If yours is front-loaded, this page is optimistic, because the early leavers are the ones you paid for most recently — and that is worth knowing before you read the trough as a floor.

Save as many versions as you like and put any two side by side, figure against figure, with the better one on each line marked and the difference in its own column. That screen is the one that decides things, and it is the part a free calculator cannot do at all. Channels differ enormously in both what they cost and who they bring, and a blended figure describes neither.

One HTML file. No account, no subscription, no internet needed. Opens on Windows, Mac and Android; the readme explains the extra step on iPhone and iPad, where Apple blocks JavaScript in downloaded files and every tool of this kind is affected.

Everything lives in your browser on your device. Nothing is uploaded, which is why it works offline and why nobody else can see your figures — and it also means clearing your browsing data deletes it. The tool does not pretend otherwise: the header shows how long since your last export at all times, turns amber after three days and red after seven, and export is one click that produces a plain file you keep.