CAC payback period calculator
Work out how many months it takes a marketing channel to earn back what it cost to acquire a customer.
CAC payback period calculator
Paste one or more marketing channels as "channel;CAC;monthly revenue;gross margin" and this tool works out how many months it takes each one to pay back its customer acquisition cost. It projects the monthly gross-profit contribution of an average customer, adds it up month by month, and reports when the cumulative total first covers the CAC — then sorts every channel from fastest to slowest payback so the ones worth doubling down on sit at the top.
The options control how realistic the projection is. Monthly churn shrinks the pool of paying customers over time, compounding month over month, so a channel that looks fast on paper can take longer once churn is factored in. Monthly expansion revenue does the opposite — it models upsells by increasing revenue per surviving customer each month, which pulls payback in. A target payback threshold flags each channel as within target, over by a number of months, or never reaching it inside a 20-year horizon. Table period sets how many months the table format prints, and currency controls how amounts are formatted.
Output comes in two shapes: a compact report line per channel with its payback period, target evaluation and total contribution, or a semicolon-separated table with one column per month — easy to paste into a spreadsheet. Both update live as you type or adjust an option, and the tool understands Windows and Unix line endings alike.
Everything runs locally in your browser. Cost, revenue and margin figures for your channels are never uploaded anywhere, so the calculator is safe to use with real budget numbers. Copy the result, download it as a .txt file, or send it back into the input to rerun with different assumptions.