What Can You Afford to Pay for a Customer?

You've been asked, or you've asked yourself, "How much should I spend to get a new customer?" The honest answer is: it depends on what a customer is worth to you. Until you know that number, every ad budget decision is a guess.

Most small business owners set ad spend by feel. They pick a round number, watch the bank balance, and pull back when it gets uncomfortable. That's how good channels get cut too early and bad ones get kept too long. The fix isn't more data, it's one calculation you can do on the back of an envelope.

This is a post about the economics of a customer: what they're worth, what they cost to win, and how long you can afford to wait before the money you spent comes back. We're not covering which metrics to track generally, because we already wrote about the marketing metrics that actually predict growth. This is narrower and more useful: the one number that decides whether your ad spend is an investment or a leak.

Before you can decide what to spend on ads, work out what a customer is worth. Multiply average order value by gross margin, factor in how often they come back, and decide how long you can afford to wait for the money to return. That number sets the ceiling on what you can pay to win one.

Start with what one order is worth

Before you calculate anything complicated, work out the gross profit on a single order. That's the money left after you've paid for the product or delivered the service, before your fixed costs like rent and software.

Take a florist. The average order is £65. The flowers, wrapping, and ribbon cost £26. The gross profit on that order is £39, which is a 60% margin. That £39 is the number that matters, not the £65. If you spend £40 on ads to win that customer, you haven't made £25. You've lost £1.

A lot of owners do this calculation on revenue instead of gross profit, and it leads them to overspend. A £1,000 order with £100 of gross profit doesn't mean you can afford to spend £500 to win it. You can afford to spend up to £100, and only if you're confident they'll come back.

Then factor in how often they come back

A single order is rarely the whole picture. Most businesses have some customers who buy once and some who come back. What you want is the average across both: the total gross profit a typical customer generates over the whole time they buy from you.

Start simple. If you run a coffee shop and the average customer spends £6 a visit, comes in twice a week, and tends to keep coming for about a year before they move or switch, that's roughly £600 of revenue a year. At a 70% margin, they're worth about £420 in gross profit over their lifetime as a customer.

You don't need exact numbers. A rough estimate from your point-of-sale data or your accounting software is enough to change how you think about ad spend. If you have no repeat purchase data at all, start with the single-order number and be conservative. Assuming customers come back when they don't is how businesses quietly go backwards.

For most small businesses, the simplest version is: average order value, times gross margin, times the number of orders a typical customer places before they drift away. That's your customer lifetime value, roughly. It doesn't need to be precise to be useful. It needs to be in the right ballpark so your spending decisions stop being random.

Decide how long you can wait for payback

Here's the part most guides skip. Even if a customer is worth £420 over a year, you don't have £420 to spend on the day they first buy. You have to spend the money first, then wait for it to come back. How long you can wait depends on your cash position.

If you have three months of operating costs in the bank, you can afford to spend to win customers who pay back over 90 days. If you're running close to the line, you need payback inside 30 days, or you run out of cash before the customers you won start paying you back.

This is why two businesses with identical customer values can afford very different ad budgets. The florist with six months of cash reserves can spend £39 to win a customer who pays back on the first order. The florist who's tight on cash needs that payback on the first order, or they're funding tomorrow's customers with today's overdraft.

Be honest with yourself about this. The number of businesses that run out of money while growing is not small. Growth eats cash, and the faster you grow, the more cash it eats. If your payback period is longer than your cash runway, you're not growing. You're borrowing time.

What doesn't matter here

A few things will tempt you off the economics. Resist them.

Follower counts, impressions, and page views don't enter this calculation. They're not worthless, but they're not money, and this is a money calculation. If you want to understand why those numbers mislead, read about the marketing metrics that actually predict growth.

Brand awareness doesn't enter it either, not directly. If you're spending on awareness before you know what a customer is worth, you're spending blind. Awareness is real, but it's not a reason to skip the maths.

And don't confuse cost per click with cost per customer. A cheap click that never converts is more expensive than a costly click that does. The only number that matters is cost per customer acquired, and the only way to judge whether that's acceptable is to compare it to what a customer is worth.

How this changes your ad budget

Once you know what a customer is worth and how long you can wait, your ad budget stops being a round number pulled from the air. It becomes a range you can defend.

If a customer is worth £150 in gross profit and you want payback within 60 days, you can afford to spend up to £150 to win one. If your ads are currently winning customers at £60 each, you have room to spend more or to test new audiences. If they're winning customers at £180 each, you're losing £30 on every sale and you need to fix the funnel or pull back, not push harder.

This is the same logic behind how to set a marketing budget for a small business, but applied to acquisition specifically. If you're spending on Google Ads, the decision of how much a small business should spend on Google Ads comes down to this same calculation: what's a customer worth, and what does it cost to win one?

What to do this week

1. Work out your gross profit per order. Take your average order value and subtract the direct cost of delivering it. That's your floor. You can never afford to spend more than this to win a one-time customer.
2. Estimate how often a typical customer comes back. Look at your last 50 customers. How many bought more than once? Use that to adjust your single-order number into a rough lifetime value.
3. Set your maximum cost per customer. Pick a payback period you can live with given your cash position, and cap your ad spend at the gross profit a customer generates within that window. If you're spending more than that today, you've found your first thing to fix.

Want help finding the gap between what you're spending and what a customer is actually worth? The $99 growth audit reviews your acquisition economics alongside the rest of your funnel and comes back with a prioritised plan in a few business days, credited in full towards any work you book within 30 days.

Frequently asked questions

How much should a small business spend to acquire a customer?

Spend up to the gross profit a customer brings in over the period you can afford to wait. If a customer is worth £300 in gross profit and you want your money back within 90 days, you can spend up to £300 to win them. Spend more than they're worth and you lose money on every sale, not make it up on volume.

What is customer lifetime value?

It's the total gross profit a customer generates across every order they ever place with you, minus what it costs to serve them. For most small businesses a rough estimate is enough: average order value times gross margin times the number of orders a typical customer places before they stop buying. You don't need precision to make better spending decisions.

How long should I wait for ad spend to pay back?

It depends on your cash position and your margins. A business with healthy margins and cash reserves can afford to wait 90 to 180 days for payback. A thin-margin business with tight cash flow should aim for payback inside 30 to 60 days, or it runs out of money before the customers it wins start paying back.

Should I spend more on ads if my customers come back often?

Often yes, but only if you can measure repeat behaviour. If the average customer buys four times a year and stays for two years, you can afford to spend more to win them than a one-time purchase would suggest. The mistake is assuming repeat business without checking whether your customers actually come back.

Sources

• Google Ads Help, About target CPA: https://support.google.com/google-ads
• Google Analytics Help, Audience reports: https://support.google.com/analytics