Cost per lead is what you pay for each enquiry. Cost per customer is what you pay for each person who actually buys. A campaign with cheap leads can still be the more expensive one if few of those leads become customers, so track both.
The two numbers
- Cost per lead: advertising spend divided by the number of enquiries.
- Cost per customer: advertising spend divided by the number of customers who actually bought.
A worked example (made-up numbers)
These figures are an illustration only. They are not real client results. Suppose two campaigns each spend Rs 100,000.
- Campaign A: 50 leads, so Rs 2,000 per lead. Two of them become customers, so Rs 50,000 per customer.
- Campaign B: 20 leads, so Rs 5,000 per lead. Eight of them become customers, so Rs 12,500 per customer.
Campaign A looks cheaper if you only look at leads. Campaign B brings customers at a quarter of the cost. The better campaign is the one with the lower cost per customer, as long as the margin on each sale supports it.
Why this gets missed
Google Ads and Meta Ads report leads easily because the form submission happens on your website. What happens afterwards, such as a call, a quotation or a sale, usually happens by WhatsApp, phone or in person, so the ad platform never sees it.
How to start tracking customers
- Keep a simple list of every enquiry with its source, such as Google Ads, Meta Ads or direct.
- Mark each lead as qualified, quoted or sold, and note the sale value.
- Every month, divide spend by qualified leads and by customers.
- Use these numbers, not clicks, to decide which campaign gets more budget.
Sending results back to Google
Google describes enhanced conversions for leads as an upgraded version of offline conversion import that uses user-provided data such as email addresses. In short, when a lead later becomes a customer, you can send that result back so Google learns which clicks led to real business. It needs the Google tag or Google Tag Manager on your site and a way to import the results, so it suits businesses with enough enquiries and a tidy customer list.
Last verified: 6 November 2026, against the Google Ads Help page below.
Sources
Quick answers
Is a low cost per lead a good sign?
Not by itself. It is only good if those leads turn into customers at a sensible rate.
Do I need special software to track customers?
No. A shared sheet with the lead source, status and sale value is enough to start.
What if my customers order on WhatsApp?
Keep the WhatsApp enquiries in the same list and note the source when the chat starts, for example by asking how they found you.
Want help with this?
Tell us about your business and goals. We will suggest a sensible starting point, with no promises of guaranteed results.