Your directory listing tells you what each lead costs, because the directory sends a monthly report saying so. Your ad account does the same. Your website assistant does not arrive with a neat number attached, which means it either gets ignored in budget discussions or gets credited with every conversation it ever had.
Neither is useful. A cost per lead for your chatbot is easy to calculate, but only if you are strict about what goes on each side of the division. Be generous with the lead count and stingy with the costs and you will produce a number that looks wonderful and misleads you.
Here is how to calculate it properly, then how to compare it with the channels you already pay for without comparing apples with invoices.
Decide what a lead is before you count
Write a definition down and use it for every channel. A reasonable one for most service businesses:
- Named. A real person or company name.
- Reachable. A working email or phone number.
- Relevant. A stated need that matches something you sell, in an area you serve.
- New. Not an existing customer asking about a current job, and not already in your system this month.
Anything that fails a test is a conversation, not a lead. A visitor asking your opening hours is valuable service, but it is not a lead. Neither is a supplier pitch, a job applicant or a student doing research. The difference between a lead and a qualified lead goes further if you want a second tier for qualified leads.
The calculation
Monthly cost per lead = (subscription + review time + any follow-up tooling) ÷ leads captured that meet the definition.
Two details make it honest.
Include time. On a flat plan the subscription is small, so the time you spend reviewing conversations and updating answers is often the largest cost. Price it at your real hourly value.
Remove duplicates. If someone chatted with the assistant and then also filled in your form, count them once. The simplest rule is first touch: whichever channel they used first gets the lead.
A worked example
These numbers are hypothetical. Replace each with yours.
A physiotherapy clinic runs a website assistant on the Pro plan at $59 a month. The practice manager spends 40 minutes a week reviewing conversations and adding answers, valued at $30 an hour, which comes to about $87 a month. Total monthly cost: $146.
In September the assistant captured 31 contact records. After applying the definition:
- Remove 4 existing patients asking about their current appointments: 27 left.
- Remove 3 with no valid contact details: 24 left.
- Remove 2 who had already submitted the contact form earlier that month: 22 left.
- Remove 1 job applicant: 21 left.
Cost per lead is $146 ÷ 21, or about $7. Using the raw 31 would have given $4.71, and the difference matters when the number goes into a budget meeting.
Now follow them through. If 7 of the 21 became booked initial assessments that went ahead, the cost per new patient is $146 ÷ 7, about $21.
Then look at the month before. If the clinic's review time was 90 minutes a week in its first month, because the manager was still writing answers, the same calculation gives a noticeably higher cost per lead. That is normal. Cost per lead from an assistant usually falls over the first few months as the knowledge base fills in and review time shrinks, so judge it on month three, not month one.
One caution for clinics and other health businesses: the assistant should give information about services, prices and availability, not clinical advice. Leads that turn out to be urgent medical questions belong with a qualified person, and should not be counted as sales leads at all.
Comparing it fairly with ads and directories
This is where most comparisons go wrong. Ads and directories send you new visitors. A website assistant converts visitors who are already on your site, some of whom arrived because of those ads and directories. They are not competing for the same job, so a like-for-like cost per lead can mislead.
| Question | Paid ads | Directory listing | Website assistant |
|---|---|---|---|
| Does it bring new people? | Yes | Yes | No, it converts existing visitors |
| How is it billed? | Per click or impression | Monthly fee or per lead | Flat monthly fee |
| Does cost rise with volume? | Yes | Sometimes | No, within the plan's allowance |
| Where do its leads come from? | Your ad targeting | Directory users | Every traffic source you have |
| Fairest comparison metric | Cost per won job | Cost per won job | Cost per won job, first touch |
The fairest single number is cost per paid job by first-touch channel. It still has flaws, but it rewards channels for work won rather than form fills.
One thing to watch: if a visitor came from an ad, talked to the assistant and became a lead, first touch gives the lead to the assistant, which makes the ad look worse. Keep a second column for traffic source so you can see both stories. Often the two columns show the assistant making paid traffic more productive rather than replacing it, which is the argument made in how to capture leads from paid traffic without landing pages.
Keeping the numbers clean each month
Counting by hand works for a few dozen leads. Beyond that, send leads somewhere they can be matched. SpideyChat's webhook action posts lead details as JSON, which can feed a CRM, a spreadsheet through Zapier or Make, or a Slack channel; the integrations page shows what connects. Once every lead from every channel lands in one list with a source field, duplicates are a sort-and-scan job.
Watch for the two common distortions:
- Junk inflation. If the lead count jumps but won jobs do not, your capture questions are too loose. How to avoid collecting junk leads covers tightening them.
- Silent time creep. If review time doubles because the knowledge base is out of date, your cost per lead rises even when the subscription does not.
Set up your tracking this week
Write your four-part lead definition and share it with whoever handles enquiries. Create one spreadsheet with columns for date, name, contact, first-touch channel, traffic source, qualified yes or no, and won job yes or no. Fill it for every lead from every channel for three full months. Only then calculate cost per won job for each channel side by side, and move budget based on that figure, not on the monthly reports the channels send you.