A cheap lead can become an expensive appointment
An advertising report shows cost per lead. Your business needs to know what it costs to create a useful appointment. Between those two points are response, qualification, scheduling, cancellation and attendance.
Cost per booked appointment is the included cost divided by the number of confirmed bookings in the defined group. The formula is simple. Choosing an honest cost boundary and denominator is the harder part.
Use the metric to compare a consistent journey, not to suggest that every appointment becomes a customer. A booking, an attended conversation and a paid job are different outcomes.
Calculate two versions
Media-only cost per booking equals ad spend divided by confirmed bookings attributed to that spend. Fully loaded cost per booking adds the costs you choose to include, such as management, software and the team's lead-handling work.
Media-only cost per booking = ad spend / confirmed bookings
Fully loaded cost per booking = included acquisition and handling cost / confirmed bookings
Cost per attended appointment = included cost / attended appointmentsState which version you report. Calling a media-only number “customer acquisition cost” obscures both the omitted expenses and the difference between an appointment and a customer.
Use a single currency. Record how you allocate shared software or team costs across campaigns. Allocation is a planning choice; changing it can change the reported result without changing customer behaviour.
Work through an invented example
Suppose a campaign spends KES 60,000 on ads. The same acquired-lead group produces 120 valid enquiries, 24 confirmed bookings and 18 attended appointments. Management, software and handling costs allocated to that group total another KES 30,000.
These are teaching numbers, not Rainlight results or market benchmarks.
| Metric | Calculation | Result |
|---|---|---|
| Media cost per valid enquiry | 60,000 / 120 | KES 500 |
| Media cost per confirmed booking | 60,000 / 24 | KES 2,500 |
| Fully loaded cost per booking | 90,000 / 24 | KES 3,750 |
| Fully loaded cost per attended appointment | 90,000 / 18 | KES 5,000 |
| Enquiry-to-booking rate | 24 / 120 | 20% |
| Booking-to-attendance rate | 18 / 24 | 75% |
If only twelve attended appointments meet the agreed fit definition, the fully loaded cost per qualified attended appointment is KES 7,500. Record qualification consistently; do not decide that an appointment was unqualified only after it failed to sell.
Match costs and outcomes to the same group
Pick leads acquired during a defined period, then allow enough time for their booking and attendance outcomes to mature. Write down the cutoff date. Some enquiries may still be open when you report.
Dividing this week's spend by this week's appointments can mix new leads with people acquired months ago. That may be a useful cash-flow view, but it is a different calculation from campaign acquisition cost.
Remove duplicate records and count a rescheduled appointment once within the journey. Decide how cancellations affect your booked metric and report cancellations separately. Excluding them without saying so can make appointment quality look better than it is.
Where attribution is uncertain, label it uncertain. A customer who saw an ad, returned through search and called the office does not supply a clean causal answer. Keep your attribution rule stable and distinguish attributed outcomes from outcomes proven to be caused by the campaign.
Diagnose the stage that needs work
High cost per enquiry points toward acquisition, offer or audience issues. Reasonable enquiry cost with weak booking suggests reviewing fit, response and the next-step path. Strong bookings with weak attendance suggests checking expectations, timing and appointment details.
These are diagnostic hypotheses, not conclusions from the ratio alone. Inspect the records. A low booking rate may reflect correct qualification. A high rate may reflect appointments with people who never wanted the service.
If there are zero bookings, report the spend and zero outcomes. Cost per booking is undefined. Do not insert a small denominator or report zero cost.
Choose a business threshold from your own economics
To estimate whether the cost is workable, use the share of qualified attended appointments that become paid jobs and the contribution available from each job after delivery costs. Treat future repeat purchases as uncertain unless your records support them.
For example, an assumed 25% close rate and KES 30,000 contribution per first job imply KES 7,500 expected contribution per qualified attended appointment before acquisition costs. That is a planning ceiling before a profit allowance, not a guaranteed break-even point.
Use actual cohorts when they become available. Rainlight's leakage calculator can explore assumptions, while the service-business briefing helps connect campaign reporting to the booking records needed for this calculation.