Payback Period by Channel

What this tool does

CM8-367 works out how long each acquisition channel takes to return what a customer cost, how much cash your current run rate has tied up, and how much faster you could grow before the money runs out.

Everything runs inside this single file — no account, no upload, no network request of any kind.

Payback is a different question from profit

A channel can be excellent on lifetime value and impossible to afford. A customer who costs 9,400 and returns 40,000 over five years is a wonderful customer — and if you win twenty a month, you are spending 188,000 a month to receive it back slowly, which is a financing problem rather than a marketing one.

The ratio of value to cost tells you whether to run a channel at all. Payback tells you how fast you can run it, and for most businesses that is the binding constraint.

What one row is

One row is one channel. Keep the channels at the level you can make decisions about — separating brand from non-brand search matters here as much as anywhere, because their paybacks differ by an order of magnitude.

Use fully loaded acquisition cost including people time. A payback calculated on media spend alone is roughly half the real one, and it is the half that flatters you.

How payback is calculated

Every figure is gross profit, not revenue. Using revenue understates payback by the whole cost of goods and is the most common error in this calculation.

Why survival weighting changes the answer

The usual sum is CAC ÷ monthly profit. It assumes every customer is still there every month until the debt is repaid, which is exactly what does not happen.

With 6.5% monthly churn, only about half a cohort remains after ten months, so month ten contributes half what the simple sum assumed. The tool shows both figures side by side in the workings table; the gap between them is the customers who left before they finished paying you back.

The gap widens sharply with churn. Below 2% a month the two figures are close. Above 5% they diverge fast, and above 8% the simple sum is close to fiction.

Channels that never pay back

This is the finding the simple sum cannot produce, and it is real. With high enough churn, a cohort's contribution flattens out before it ever reaches the acquisition cost: the customers leave faster than they repay, and no amount of waiting fixes it.

The tool reports never rather than a number, and the cumulative curve chart shows it directly — the line flattens below the dashed acquisition-cost line and stays there. The sample includes one of these deliberately.

A channel that never pays back has exactly three fixes: cut its acquisition cost, raise the monthly gross profit, or improve retention for the customers it brings. Spending more is not one of them.

Money at the start

Anything received before the monthly contribution starts — a deposit, a first order, an annual payment — goes in as gross profit received at the start and is recovered immediately. It is the single most powerful lever on payback and the one most businesses never try.

The enterprise channel in the sample costs 9,400 to acquire and receives 4,200 of gross profit at the start because contracts are paid annually in advance. Without that, its payback would be roughly twice as long, and its cash requirement twice as large.

Ramp and collection delay

Ramp is the months before a customer reaches full spend — a trial converting to a paid plan, a partner learning to sell, an account growing into its allocation. Contribution builds evenly from zero to full across those months.

Collection delay is the gap between invoicing and the money arriving, including how late customers actually are rather than what your terms say. It is added directly to the payback because cash you are owed is not cash you have. Sixty-day terms add two months to every channel they touch.

The cash tied up

In steady state you have several cohorts part-way through repaying at any moment: the newest has repaid nothing, the oldest has almost finished, and on average half of each is outstanding. That is what the division by two represents.

It is an approximation and it is stated as one. It assumes a steady run rate and even repayment; neither is exactly true. For deciding how much working capital growth needs, it is close enough, and it is far better than the usual answer, which is nothing at all.

For a channel that never pays back, the whole spend over the horizon is treated as tied up, because none of it comes back.

How fast you can grow

The growth table is the practical output of this tool. It shows what several run rates would tie up against the cash you said is available, and the foot gives the ceiling — the multiple of today's spending that would consume all of it.

Two things to remember when reading it. The ceiling assumes nothing else needs that cash, which is never true: stock, wages and tax all have first call. And acquisition cost rises as you scale a channel, so doubling spend rarely doubles customers — the real ceiling is lower than the arithmetic suggests.

What to do with it

• Shift spend towards short-payback channels when cash is tight, even where a slower channel is more profitable over a customer's life. Fast payback is what lets you reinvest.
• Ask for money earlier. An annual plan at a discount, a deposit, a first-order minimum. Discounting for payment up front is often the cheapest financing a business can get.
• Fix collection. Sixty days of unnecessary delay across every channel is months of growth foregone, and it costs nothing to fix except discipline.
• Fix retention before spending more. Churn moves payback and lifetime value at the same time; nothing else does.

What this is not

• It is not a cash flow forecast. It says how much acquisition spend is outstanding, not what your bank balance will be.
• It ignores tax, stock, capital spending and everything else competing for the same money.
• It assumes a steady acquisition rate. Lumpy channels such as trade shows are smoothed to a monthly average here, which is fine for planning and wrong for any individual month.
• It assumes constant churn, when early churn is usually higher — which means real paybacks are slightly worse than these.
• It says nothing about whether a channel can absorb more spend at the same cost.

Printing and sharing

The Report tab prints the tiles, charts and both tables with a title block you fill in. The growth table is the one to take to a finance conversation — it turns "we would like a bigger budget" into a specific working capital requirement.

Saving your work

Channels are held in this browser, on this computer, and stay there between visits. Use the backup button to write a JSON file you control.

Accuracy & disclaimer

Every input here is yours and the tool applies the arithmetic above exactly. It is not financial advice, and the cash figures are an approximation of one part of working capital rather than a forecast of the business.