Measuring cost per lead and the mistakes that distort it

Cost per lead is the easiest number in marketing to calculate and the easiest to misread. This page explains the sums, what to put into them and where they go wrong. The calculator that does the arithmetic is here, and the overall process is in how UAE businesses get leads, what a lead costs and how leads are followed up.

Three costs, not one

• Cost per lead = total spend / leads received.
• Cost per qualified lead = total spend / (leads x qualified share).
• Cost per customer = total spend / (qualified leads x share that become customers).

These are my definitions, set out so the arithmetic is visible. They are not a standard. The further down the list you go, the closer the number is to what the business actually pays to win work, and the fewer cases it rests on. I give no typical figure for any of the three.

What goes into spend

Decide once what counts as spend and keep to it: platform spend, agency or management fees, call tracking, software and the cost of creating the pages leads land on. Say whether amounts include VAT. If you compare a source whose cost includes fees with one that does not, the comparison tells you about your bookkeeping, not about the sources.

What goes into leads

Google defines a conversion as an interaction that leads directly to a behaviour valuable to you, and gives a phone call as an example^[3]. Cost per lead moves with whatever you decide to count. If calls, forms and messages are all counted as leads, say so and keep each type visible, because they rarely qualify at the same rate. Remove obvious duplicates and spam before you count, and say that you did.

Connecting leads to customers

The share that qualify and the share that close must come from your own records, for the same source and period. For paid clicks that become sales offline, Google describes saving the click ID that it assigns to each ad click with the lead’s details, then sending the outcome back when the lead converts^[2]. If you collect leads through lead forms, remember that Google keeps those leads for 60 days^[1], so record the outcome in your own system as well.

Common mistakes

• Comparing sources on cost per lead when their leads qualify at different rates.
• Counting a lead the moment it arrives and a customer months later, in the same period.
• Leaving out fees, tools or creative from spend for some sources and not others.
• Reading one month with a handful of leads as a trend.
• Treating a platform report as the end of the record, when the sale happened in your own system.
• Leaving referrals and calls out of the count because nothing tracks them automatically.

A calculation of your own numbers is not a forecast. If you want the offline outcomes sent back to the ad platforms, my offline conversion tracking service is described on my own site, and I sell it, so the publisher disclosure applies. For how leads are delivered in the first place, see lead sources and how each one delivers leads.