Cost per lead is the metric everyone quotes - and it's the one that hides the truth. A campaign with a cheap cost per lead can quietly lose you money, while one with a "high" cost per lead prints profit. The number that actually grows revenue is cost per booked order.
Why cost per lead misleads
A lead is just a contact detail. It tells you nothing about whether that person is qualified, in your area, has the budget, or will ever turn into a paying job. Two campaigns can both deliver leads at £20 each - but if one sends tyre-kickers and the other sends ready-to-buy homeowners, they are not the same campaign. Optimising for the cheapest lead almost always optimises for the worst leads.
Optimising for the cheapest lead almost always optimises for the worst leads.
Follow the money down the funnel
To see what's really happening, track every stage, not just the top:
- Cost per lead - what you pay for a raw enquiry
- Lead-to-appointment rate - how many are qualified enough to book a visit
- Appointment-to-sale rate - how many become paying jobs
- Cost per booked order - total spend ÷ jobs won
- Return on ad spend (ROAS) - revenue ÷ spend
A worked example: Campaign A delivers leads at £15 but only 1 in 20 becomes a job - that's £300 per order. Campaign B's leads cost £40, but 1 in 5 converts - £200 per order. Campaign B looks "expensive" on cost per lead and is actually a third cheaper where it counts.
Why this changes how you run ads
Once you measure cost per order, your whole approach shifts. You stop chasing cheap clicks and start qualifying harder - tighter targeting, better-fit keywords, honest landing pages that pre-frame price, and questions in the form that filter out the wrong jobs. You'll happily pay more per lead because each one is worth more. This is the principle behind our PPC management: we're measured on booked jobs, not clicks.
Close the loop with your sales data
The reason most firms can't measure cost per order is that ad data and sales data live in different places. Connect them: pass conversion data back from your CRM to Google and Meta so the platforms learn to find more of the people who actually buy - not just the people who fill in forms. When the feedback loop is closed, the algorithms optimise toward revenue automatically.
The bottom line
Cheap leads are easy to buy and easy to be fooled by. Booked orders are what grow the business. Measure to the order, optimise to the order, and judge every campaign on the only number that pays your wages. Want it set up properly and reported in plain English? That's exactly what we do inside our PPC management.
