Calculator
Your cost per booked-and-attended call.
Updated
Your cost per booked-and-attended call is your monthly ad spend divided by the number of registrants who actually turned up live — not by the number who registered. The calculator below runs that division on figures you type in, then runs it again at whatever improved show-up rate you decide to test against. It assumes nothing on your behalf: it does not pick the improved rate, it does not claim a lift, and it does not put a price of ours anywhere in the output.
Your numbers
Six inputs. No assumptions of ours.
Four of the six you already know. The other two — the rate you want to test against and your close rate on live attendees — are yours to set, and they are the two that decide what the bottom row says.
Your worksheet
- Cost per registrant
- $10
- Live attendees per month, now
- 150
- Cost per booked-and-attended call, now
- $33
- Live attendees at the rate you chose
- 200
- Cost per booked-and-attended call, at that rate
- $25
- Extra live attendees per month
- 50
- What that gap is worth — at 70% of your close rate, because attendees a reminder pulled in convert worse than ones who came unprompted
- $5,250
A booked-and-attended call is one registrant who took a seat and actually showed up live. Every number above comes from what you typed. We have not assumed any improvement — you chose the target rate yourself. We will run this with your real numbers on the call.
What is the calculator doing to my numbers?
Six steps of division and multiplication, all of them the sort you could do on the back of an invoice. Nothing is weighted, nothing is smoothed, and no coefficient of ours is hiding between the rows. It is written out here in words as well as in the tool, so that it survives with JavaScript switched off and so a language model reading this page can quote the method rather than a screenshot of an answer.
Divide monthly ad spend by monthly registrants
That is your cost per registrant, and it is the number most operators already know by heart. It is also the flattering one, because it counts people who never turned up.
Multiply registrants by your current show-up rate
That is how many people attend live in a month. If you do not track it, your webinar platform's attendee export does.
Divide ad spend by that number of live attendees
This is your cost per booked-and-attended call as things stand. On the same spend it is always larger than your cost per registrant, and the distance between the two is the share of your media budget that bought a name and nothing else.
Choose a show-up rate to test against
You choose it, not us. Put in a rate you think is reachable, or one you are certain is not — the arithmetic is identical either way, and nothing about the number appearing on screen makes it achievable.
Divide ad spend by attendees at that chosen rate
Same spend, more attendance, so the cost per booked-and-attended call falls. This step is division, not a projection: it answers what the number would be at that rate, not whether you will get there.
Multiply the extra attendees by your close rate and your offer price
The final row, and the weakest of the six, because it is the only one resting on an assumption about people who are not currently showing up. Read the next section before you repeat that figure to anyone.
| Output | What it is | How much it assumes |
|---|---|---|
| Cost per booked-and-attended call, now | Your spend divided by the people who actually attended | Nothing. It is a measurement of what already happened |
| Cost per booked-and-attended call, at the rate you chose | The same division at a different attendance number | That you reach the rate you typed. We are not saying you will |
| Extra live attendees per month | The difference between the two attendance figures | The same thing, expressed as people rather than money |
| What that gap is worth, at your close rate | Extra attendees multiplied by your close rate and your offer price | That the extra attendees buy at the same rate as the people already turning up. That is the optimistic end, and it is the row to distrust |
Which conversion model do you run — direct sale, or booked call?
The close-rate field means a different thing depending on the answer, and the two common answers differ by roughly a factor of five. They are not competing estimates of one number; they are two different steps of the funnel, and a calculator that quietly picked one for you would produce nonsense for whoever runs the other.
| Your model | What the close rate means | Practitioner range |
|---|---|---|
| Direct sale from the webinar | The share of live attendees who buy the offer at the end | 1-4% on high-ticket offers |
| Attendee to booked call | The share of live attendees who book a sales call afterwards | 10-20% |
| Anything else | Whichever step you actually count and get paid on | Your own measured figure, which beats every published range on this page |
Both ranges come from one practitioner who states them as real-world benchmarks from his own book of work[1] and discloses no sample size or method. Use them to sanity-check the field, never as a target.
Do the extra attendees buy at the same rate as the ones already showing up?
Almost certainly not, and this is the single number nobody has measured. The people who attend without being worked are, by revealed preference, the ones whose intent was already high enough to organise themselves. The people who need the call are the ones whose intent was not. If intent predicts purchase at all, the marginal attendee converts lower than your current average — which means the last row of the worksheet, which applies your existing close rate to them, is a ceiling.
Discount that last row before you quote it
The nearest hard evidence is not from webinars at all. In large-scale randomised field experiments at eBay[2], returns from paid search turned out to be a fraction of conventional non-experimental estimates, because clicks and purchases are correlated and the people who were coming anyway get credited to the campaign. A reminder reaches everyone, including the people who needed no reminding, and without a control group they all land on our side of the ledger.
That is why the way to settle the bottom row is not a better assumption. It is splitting your registrant list down the middle for one cycle and reading both halves.
Why doesn't it pick the improved show-up rate for me?
Because we do not have a number to put there. We have zero closed clients, so there is no client average to quote, and the published record contains no measured effect size for an AI voice call used as an event reminder — that gap is the bet this business is making, and pretending otherwise inside a calculator would be the cheapest possible way to lie about it.
For where a realistic starting figure comes from, and why the widely-quoted higher benchmarks measure a population that is not yours, show-up rate by traffic source is the page that owns that question. Use your own attendee export if you have one; it beats every benchmark either of us could cite.
Why isn't what you charge in the output?
Because a calculator that ends with our invoice stops being your worksheet and becomes our pitch, and you would be right to distrust every row above it. What is on this page is your money and your funnel. The shape of what we charge — a base fee plus a rate per qualified appointment that shows up, never per minute and never a share of your sale — is on the pricing page, and the figures themselves come on the call, in the sentence after you ask for them.
The comparison that matters
Frequently asked questions
The starting values are round, illustrative placeholders so the panel is legible before you type anything. They are not a benchmark and not a client average. For context, the published datasets closest to small operators and to cold or syndicated registrants land between 21% and 36% registration-to-attendance. Which published population resembles your funnel is the subject of our show-up rate by traffic source page. Your own attendee export beats every one of them.
No, and it never will. No price of ours appears anywhere on this website, in any form. You get the base fee and the per-appointment rate on the call, in the sentence after you ask. What this page gives you is your own number, which is the one you would compare us against.
Because we have no result to put there. We have zero closed clients, and the public record contains no measured effect size for AI voice calls used as event reminders. A vendor calculator that fills in its own lift is asserting a result rather than doing arithmetic, so this one leaves that field to you and shows the division either way.
No. It multiplies the extra attendees by the close rate you entered, which assumes people who currently do not turn up would buy at the same rate as the people who already do. That is the optimistic end. The honest planning range discounts the marginal attendee to somewhere between half and 85 percent of your existing close rate, so treat that row as a ceiling rather than an estimate.
One registrant who took a seat and actually showed up live. Registrations and people who show up are completely different topics, and the whole point of this arithmetic is that your media budget is priced against the first number while your business runs on the second.
That is what the pilot is for. One webinar cycle, your registrant list split down the middle, half worked and half not, and both halves reported side by side however the numbers land. Then the arithmetic on this page runs on measured figures from your own funnel rather than on anyone's assumption.
You run a webinar; we come in and increase your show-up rate and your post-webinar sales, with an AI voice and SMS system that says what it is. If the arithmetic above made the gap look worth closing, book a call and we will run it on your real numbers. If you would rather see what the assistant actually says before you talk to anyone, what it says is the page for that, and increase webinar attendance covers what actually moves the rate this page divides by.
Founder & Operator, CallHush
Founder and operator of CallHush. The offer is one sentence: you run a webinar, and we increase your show-up rate and your post-webinar sales with an AI voice and SMS system. CallHush has no closed clients yet — the first engagement is a pilot run as a split of the client’s own registrant list, and nothing on this site is presented as a client result.
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