Unit Economics on One Page Win Customers at a Profit

Customer cost, gross margin and payback on one page, with an illustrative café. If a customer costs more to win than they pay, growth hurts.

Picture a café owner who is thrilled. Her ads are working. Forty new people walked in this month. Then she sits down with the numbers and finds she is poorer than before.

That can happen. When it costs more to win a customer than that customer will ever pay you, every new customer makes the hole deeper. Growth turns into a faster way to lose money.

Here is a one-page check that shows whether that is happening. It uses three ideas: customer acquisition cost, gross margin and payback. All the numbers below are illustrative. I made them up to show the maths. They do not describe any real café.

Three terms, in plain words

Customer acquisition cost (CAC) is what you spend to win one new customer. Add up the ads, the free coffees, the discounts and the time. Divide by the number of new customers it brought.

Gross margin is what is left from a sale after the direct cost of making it. For a coffee, that is the beans, milk and cup. It is not rent, wages or electricity. Those come later.

Payback is how long a new customer takes to give back what you spent to win them.

An illustrative café

Say a customer spends $8 per visit. The beans, milk and cup cost $2.40. So 70% of the sale is gross margin. That is $5.60 per visit.

Now say a typical new regular comes twice a month and stays for six months. That is 12 visits. Twelve visits at $5.60 is about $67 of gross profit over the customer's whole stay.

Next, the cost of winning that person. Suppose the café spends $1,200 on ads and welcome offers in a month and gains 20 new regulars. CAC is $60.

Compare the two numbers. You spend $60 to earn $67. You are ahead by about $7 per customer. Payback takes about 11 visits, so a little over five months.

That is thin. Rent and wages still have to come out of that $7.

When growth makes it worse

Now change one thing. A new ad channel costs more, and CAC rises to $90. Same customer, same $67 of gross profit.

You now lose about $23 on every person you win. Win 20 more customers and you are down around $460. Win 200 more and you are down about $4,600. The bigger the campaign, the bigger the loss.

This is why "we are growing fast" can be a worrying sentence. Growth is only good when the average customer pays back more than they cost.

Three ways out

When the numbers look like that, there are only three levers.

1. Lower the cost to win. Ask your regulars to bring a friend. Referrals usually cost less than ads. Make the first visit so good that people talk about it.
2. Raise what each customer is worth. Add a pastry at the till. Offer a loyalty card that nudges one more visit a month. A small rise in spend or visits changes the whole sum.
3. Improve the margin. Look at the direct cost

Notice that none of these says "get more customers". Fix the maths first. Then add fuel.

A word of caution

Real life is messier than a clean example. Some customers leave after one visit and some stay for years. Averages hide that. Many small owners don't track exactly how often a regular comes back, so the inputs are often guesses.

So treat this check as a rough guide, not a verdict. A rough number still beats a feeling. And remember that rent and wages sit below gross margin. A customer who pays back their CAC is not yet a profit.

Count every cost of winning

Owners often leave things out when they add up CAC. They count the ad bill but not the free coffees, or the hours spent making posts, or the staff time on a launch event. If a cost exists only because you were trying to win customers, it belongs in the number.

It also helps to use a recent group of customers. Look at everyone who first came in during the last three months, and see how many returned. Their real behaviour is a better guide than a guess about "typical" customers.

If you can't yet say who came from which ad, start by writing down how each new customer found you. A simple question at the till is enough. After a month you will see which source brings people and which one is only costing you money.

Try this week

Take a piece of paper. Write down four numbers: your average sale, your gross margin in percent, how many times a typical customer buys during their stay, and what you spent last month to win new customers. Divide, compare, and see which side is larger.

What I take from this

Before I put money behind growth, I want to know whether one new customer pays back what they cost. If I can't answer that, I'm not ready to spend more.

Sources

• In-house explanation. Every number in this article is illustrative.
• Terms (customer acquisition cost, gross margin, payback) are used in their standard business meaning.