You will be able to calculate payback period and explain why it matters for a business with limited cash.
Farah's numbers from lesson 8.2 looked reassuring at first. Customers from Google search were worth about S$96 in first-year margin and cost about S$48 each to win. Customers from Meta ads were worth about S$60 and cost about S$40. Both channels earned back more than they cost within a year, so she planned to spend more on both in the run-up to Hari Raya.
Then she looked at her bank balance. The ads would be paid for in March, while the margin from those customers would trickle in over the following twelve months, and she had festive stock to buy at the same time. Whether a customer paid back mattered less, that month, than how long it would take.
Payback period is the number of months it takes for a new customer's gross margin to cover what it cost to win them. The simple version divides acquisition cost by the gross margin a customer brings in each month:
payback period in months equals acquisition cost divided by monthly gross margin per customer.
For a subscription or monthly fee, the monthly margin is easy to see. Priya's students pay S$320 a month at about 60 percent gross margin, which is S$192 a month (example figures from lesson 8.2). Her blended acquisition cost was S$200. Payback: S$200 divided by S$192, or just over one month. After the first month's fee, a new student has covered what it cost to win them.
For a shop where customers buy now and then, spread the first-year margin across twelve months to get a monthly figure. Farah's Google search customers bring S$96 a year, or S$8 a month. Her Meta customers bring S$60 a year, or S$5 a month.
For Google search, S$48 divided by S$8 a month gives 6 months, while for Meta ads, S$40 divided by S$5 a month gives 8 months. The Meta customer is cheaper to win, yet takes two months longer to pay back. Spreading the margin evenly is a simplification, since in practice a big share of it comes with the first order, but it gives a fair way to compare channels with each other.
A channel can look excellent on lifetime value and still cause trouble, because the cost comes first and the value arrives later.
Imagine a channel whose customers are worth a great deal over three years but take twelve months to pay back. Every customer you win this month is money out now and money back next year. If you double spending on that channel, you double the cash going out before any comes back. The more successful the channel, the deeper the hole gets in the short run. Businesses have run out of cash while acquiring customers who would have been profitable eventually.
Payback period makes this visible. It turns "this channel is worth it" into "this channel ties up our money for this many months", which is a question about the bank account rather than the spreadsheet.
For a large company with investors and credit lines, a long payback can be acceptable, because it has money to wait with. A small business usually does not. The owner's savings, a small overdraft and next month's sales are all there is. Cash runs out long before lifetime value has a chance to arrive.
That is why small businesses usually care more about payback than lifetime value. Lifetime value tells you whether a customer is worth winning at all. Payback tells you whether you can afford to win many of them at once, and how quickly the money comes back to spend again.
For Priya, with payback of about a month, spending more on channels that bring students is low risk for her cash, as long as she has seats in her classes. For Farah, every extra dollar on Meta ads in March comes back over eight months, and she needs to check that the business can carry that alongside stock purchases before the festive season.
Note that the comparison between channels may change if the acquisition costs are calculated differently. The per-channel figures depend on attribution, as lesson 8.1 explained, so treat payback by channel as a guide and the blended figure as the anchor.
If you took Digital marketing foundations: strategy before tactics, lesson 6.3, What a customer is worth and what you can pay for one, gave you a first view of this idea, worked out from rough assumptions before you had campaigns running. Here you compute it from data: acquisition costs from your real spend and customer counts, margin from real orders, and payback from the two together.
Expect the real figures to differ from your early assumptions, sometimes a lot, and expect to learn more from the gap than from either number on its own. Revisit your payback figures each quarter, and when a channel's payback stretches, look at whether acquisition cost has risen or customer value has fallen, since each calls for a different response.
With payback worked out for your own biggest channels, the question of where the next few hundred dollars should go gets much easier to argue.
Calculate the payback period for your two biggest channels and write which one you would put the next S$500 into and why.
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