What should you pay to acquire a customer?

Every owner who has ever run ads has asked some version of this: what is a good cost per lead?

It is the wrong question, asked for the right reason. Here is the right one, and the arithmetic to answer it for your business specifically.

Why published benchmarks will mislead you

You can find a number online for “average cost per lead” in almost any industry. It will be wrong for you, because it averages across:

• Businesses selling a $199 first job and businesses selling $60,000 contracts
• Markets where a click costs a fraction of what it costs in Los Angeles
• Agencies counting a form fill as a lead and agencies counting a signed customer
• Businesses closing 60% of their enquiries and businesses closing 15%

A benchmark that averages those tells you nothing about whether your campaign is working. Worse, it gives you a number to feel good about while you lose money.

Four numbers, in order

Cost per lead is nearly meaningless. These four are what actually decide whether marketing pays.

1. Cost per qualified enquiry. Ad spend divided by enquiries from someone who could actually buy. Not raw form fills. Not wrong numbers. Not recruiters.

2. Contact rate. The share of qualified enquiries you actually reach. This is a phone and follow-up number, and it silently inflates your real acquisition cost when it slips.

3. Enquiry-to-sale conversion. The share of conversations that become customers. This is your sales process, your pricing presentation, and how fast you respond.

4. Average first purchase, and lifetime value. What a new customer spends the first time, and what they spend over a year or two. Whether repeat business exists is what decides how aggressively you can bid.

The arithmetic

Work backwards from the value, not forwards from the ad spend.

Value of one qualified enquiry
  = average first purchase
  × enquiry-to-sale conversion
  × contact rate
  × gross margin

That is what one enquiry is worth to you, in gross profit, before you have paid for a single click. Your maximum sustainable cost per enquiry is some fraction of it — how large a fraction depends on how much of that margin you are willing to reinvest in growth, and on whether you are counting lifetime value or only the first sale.

A worked example, with invented numbers

These figures are illustrative, chosen to show the mechanics. They are not benchmarks and they are not from any client.

• Average first purchase: $4,000
• Enquiry-to-sale conversion: 25%
• Contact rate: 70%
• Gross margin: 40%

$4,000 × 0.25 × 0.70 × 0.40 = $280 of gross profit per qualified enquiry

If you are willing to spend a third of that first-sale margin to acquire the customer, your ceiling is roughly $93 per qualified enquiry on first-purchase economics alone. If customers reliably come back and your annual value is three times the first sale, the same appetite supports a much higher number — and that is a decision about cash flow and confidence in retention, not a marketing question.

Run those four numbers for your own business. The result is your target. Anyone quoting you a target before asking for them is guessing.

Where the leverage actually is

Notice which variables move the answer most.

Contact rate is the cheapest fix in the business. Going from 60% to 80% improves your effective cost per customer by a quarter and costs you nothing but a follow-up sequence and someone answering the phone. No campaign change competes with that.

Conversion is a process, not a personality. Businesses that present pricing consistently, offer a clear next step, and follow up within 48 hours convert measurably better than businesses that improvise.

Service mix beats bid tuning. Shifting budget toward the work with the margin you want changes profitability more than any amount of keyword optimisation.

Speed of response. The business that answers first usually gets the job. If enquiries sit for a day, the campaign is not the problem.

What to demand from any agency

• Report cost per customer, not cost per lead. If they cannot connect spend to sales, they cannot manage this.
• Report by service. A blended number hides both your best and your worst campaign.
• Reconcile against closed revenue at least monthly.
• Own nothing. The ad account, the conversion actions and the history should be in your name — so if you leave, you keep the data that made the number meaningful.

And the measurement part

None of this arithmetic exists unless the ad platforms are told what a sale is. That is the step most engagements skip: the pixel fires on the thank-you page, everything downstream is invisible, and the report reverts to clicks because clicks are all anyone wired up.

We wrote about what an agency report should lead with and what to check before your trackers become a legal problem.

Do the arithmetic first. Then insist the measurement is built to collect it.