How to calculate cost per booked inspection by channel

Cost per booked inspection, or CPBI, tells you what one channel paid to put one inspection on your schedule. It sits at the end of a chain that starts with clicks and leads. Each step in that chain has its own cost, and a cheap early step can hide an expensive result. For the wider view of where inspection leads come from, start with our home inspector lead generation guide.

Ad platforms report the steps they can see. Local Services Ads are Google's ads that charge per lead instead of per click. Google's help page on the Local Services Ads move to Google Ads describes the "Cost / conv." column as "your average cost-per-lead." Leads there include phone calls and messages. Any one lead might be a buyer ready to book a sewer scope, or it might be someone calling every inspector in town for a price.

The formula is total cost for one channel in one period, divided by the inspections that channel booked in that period. The real work is deciding what counts on each side of the division. Once you decide, keep those rules the same every month.

1. Pick the period. A calendar month works for most firms.
2. Add up every cost for the channel in that month, using the list below.
3. Count the inspections that channel booked in the same month, using the source on each booking.
4. Divide total cost by booked inspections.
5. Repeat the math for every channel, with the same rules each time.

What counts as cost

• Ad spend, as billed by Google, Meta or another platform
• Management fees for whoever runs the channel, in-house or outside
• Membership and per-lead fees on third-party lead platforms
• Tools tied to one channel, such as call tracking numbers
• Hard costs of agent marketing, such as lunches, room rental for CE classes and printed material

What counts as a booked inspection

Count an inspection when it is on the schedule with a date, not when the lead first calls. Decide up front how you treat cancellations, and apply that rule to every channel. Treat add-ons like radon or a sewer scope as part of the same booking, so one client counts once.

Here is the math for one month at a made-up inspection firm. The numbers are for illustration only. They are not benchmarks, and your market will look different.

On cost per lead, Meta looks like the winner at $24. On cost per booked inspection, it is the most expensive channel at $200, because only 3 of its 25 leads booked. In this example, Local Services Ads book at the lowest cost, even though their leads cost almost as much as Search leads.

The booking rate explains the gap. Divide booked inspections by leads, and you get 30% for Search, 50% for Local Services Ads and 12% for Meta. Google Ads figures its own conversion rate the same way, by dividing conversions by the ad interactions that can be tracked to a conversion in the same period.

Compare CPBI with what a job earns

A CPBI only means something next to your own numbers. Take your average fee per booked inspection, then subtract inspector pay, travel and software. If a channel's CPBI is higher than what's left, every booking from that channel loses money.

You can't divide by booked inspections until each booking carries its source. Online bookings, phone calls and agent referrals each need their own method.

Online bookings

Tag every link to your online scheduler with UTM codes, the short tags added to the end of a link that name where a visitor came from. Google's guide to campaign URLs says that when you add parameters to a URL, "you should always use utm_source, utm_medium, and utm_campaign." Pick one naming pattern, such as utm_source=google with utm_medium=cpc (cost per click), and never change it.

Spectora's support article on scheduling data says its External Scheduling Data export includes "UTM Codes" and downloads as a CSV file. Spectora also says it does not have a direct Google Analytics integration at this time. Our guide to tracking Spectora bookings in Google Analytics walks through the setup. If you book through ISN or HomeGauge, check that software's help center for where booking source is stored.

Phone calls and agent referrals

• Give each paid channel its own tracking phone number, so calls sort by source on their own.
• Ask "How did you hear about us?" on every call, and choose the answer from a fixed list.
• Record the referring agent's name on every agent booking.
• Log the source when the booking is made, not weeks later from memory.

A form fill tells you a lead came in, not that it booked. Google's offline conversion import lets you report what happened after the click.

Google's page on offline conversion imports says Google Ads gives a unique ID, called a Google Click ID or GCLID, to every click that comes to your website from an ad. When that person later converts offline, you give the GCLID back to Google Ads with details about the conversion. Google describes this as a way to measure "what happens in the offline world after your ad results in a click or call."

The booking record has to hold the GCLID for this to work. In our experience, forms that come through Spectora don't carry ad click IDs or UTM codes, and Spectora has no automated way to send booked inspections back to Google or Meta as offline conversions. That means your own website form has to capture the click ID and pass it into each lead. Our Spectora marketing setup uses forms that read a 90-day first-party attribution cookie, which is one set by your own website, so each lead carries its GCLID. For the wider ad plan, see our home inspector paid ads guide.

Channels without a media bill still cost money. Agent referrals take your time, lunches and the CE classes you host. Put an hourly value on the time you or your office manager spend, or the channel will always look free. Our guide to working with real estate agents covers that channel in depth.

SEO and content cost a monthly fee or staff time, and they don't pay back in the month you spend. Our homepage says SEO and AI search "build over months, not weeks." Measure these channels over a rolling quarter as well as monthly, so one slow month doesn't sink them.

One month of CPBI is a snapshot. Small numbers swing hard, and one extra booking from Meta in the example would cut its CPBI from $200 to $150. Look for a pattern across several months before you cut or scale a channel.

Watch the lag between lead and booking. A buyer may call in late March and book in April, once an offer is accepted. Pick one rule, either the month the lead came in or the month it booked, and use it for every channel. Compare this spring with last spring, not with the winter months.

• CPBI falling while bookings rise: add budget in small steps.
• CPBI rising for three months: check your tracking first, then the ads.
• Cheap leads but few bookings: look at follow-up speed and lead quality before cutting the channel.
• No source data: fix tracking before you judge the channel at all.