The short definition
Cost per lead (CPL) = money spent on a channel ÷ leads that channel produced.
Spend $900 on ads, receive 30 enquiries, and cost per lead is $30.
What counts as a lead
This is where the number quietly becomes meaningless. If "lead" includes every form submission, every phone call including wrong numbers and suppliers, and every chat conversation, the figure flatters itself.
Define it once and apply it consistently: an enquiry from a genuine potential customer about work you do. Then the comparison between channels means something.
Why optimising for it goes wrong
Because it ignores what happens next.
A marketplace lead sold to four contractors may cost $40 while your close rate on it is one in eight. An enquiry from your own site may cost $90 with a close rate of one in three. The cheaper lead costs $320 per job; the dearer one costs $270.
Chasing CPL would tell you to buy more of the worse channel.
The number to use instead
Cost per booked job. Spend divided by jobs won, not leads received.
It requires you to record which enquiries closed — which no platform does for you — and it is the difference between marketing measurement and marketing theatre.
What a lead should cost you
There is no published benchmark worth using, because averages blend businesses with nothing in common. Calculate your own ceiling:
Average job value × gross margin × close rate = what a lead is worth.
A $600 job at 45% margin with a one-in-four close rate makes a lead worth about $67 in gross profit. Pay below that and you are ahead before overhead.
The lifetime value adjustment
If customers return — maintenance plans, annual service, repeat repairs — first-job value understates the truth, sometimes badly. Businesses that ignore repeat value systematically under-invest in acquisition and cannot understand how competitors afford to outspend them.
When CPL is genuinely useful
Comparing two campaigns within the same channel, aimed at the same service, where close rates are similar. There it isolates the variable you are testing.
Across different channels with different lead quality, it misleads more often than it helps.
Working out your figures
Run the calculation above with your last twenty invoices. It takes fifteen minutes and it replaces every benchmark you have read.
Frequently asked questions
How is cost per lead calculated?
Money spent on a channel divided by the leads it produced. $900 of ad spend producing 30 enquiries gives a cost per lead of $30.
Why is cost per lead misleading?
It ignores close rate. A $40 lead you close one time in eight costs $320 per job; a $90 lead you close one in three costs $270. Optimising for CPL would push you toward the worse channel.
What should I measure instead?
Cost per booked job — spend divided by jobs won. It requires recording which enquiries closed, which no platform does for you, and it is what separates measurement from theatre.
What should a lead cost in my trade?
No published benchmark is worth using. Calculate your ceiling: average job value × gross margin × close rate. That figure is specific to you and changes when your pricing or close rate does.