Picture this. You spend three weeks building a webinar. You write the slides, record the intro, set up the funnel. You run some ads, get a few hundred sign-ups, feel good about it. Then the day arrives. Forty people show up. Three buy. You made $3,000 and you have no idea why it didn’t work, or what you’d need to do to hit $50,000 instead.

I’ve watched this exact scenario play out hundreds of times. In 10 years building and optimizing 114 webinars from scaling Mindvalley from $25M to $75M, to running campaigns for Tony Robbins that took ROAS from 100% to 388% the single most common mistake isn’t a bad slide deck or a weak offer. It’s that course creators build the webinar first and do the math never.

The math isn’t complicated. But if you don’t do it before you launch, you’re flying blind. You don’t know how much traffic you need. You don’t know what your registrant target should be. And when the numbers come back short, you have no idea which lever to pull. That’s not a marketing problem it’s a planning problem.

This article walks you through the exact formula I use with every client before we build anything: a reverse-engineering process that starts with your revenue goal and works backwards to a specific registrant number. By the end, you’ll know exactly how many people need to sign up for your webinar to hit your target and which variables to focus on if you’re not there yet. If you want the full system for what happens once those registrants show up, start with How to Run a High-Converting Webinar: The Complete System for Course Creators this article is the math that feeds into that system.

Why You Need to Do the Math Before You Build

Most people set a vague revenue goal “I want to make $50K from this webinar” and then build the webinar and hope. Hope is not a strategy.

When you do the math first, three things happen. You find out whether your goal is realistic given your current audience size. You identify exactly which number in the chain is the weakest link. And you stop treating the webinar as a creative project and start treating it as what it actually is: a revenue-generating system with measurable inputs and predictable outputs.

The formula is sequential. Each step depends on the one before it. Miss one, and the whole model breaks. So let’s go through it, step by step.

The Reverse-Engineering Formula, Step by Step

Step 1 Set Your Revenue Goal

Start here. Pick a number. Not a range, not a vague ambition a specific revenue target for this webinar. Let’s use $50,000 as our working example throughout this article.

Step 2 Know Your Price

What is your course or program priced at? Be precise. For the example: $1,000.

Step 3 Calculate Sales Needed

Divide your revenue goal by your price.

$50,000 ÷ $1,000 = 50 sales.

That’s the number of customers you need. Everything else in this formula is about figuring out how many people need to enter the top of the funnel to produce those 50 buyers at the bottom.

Step 4 Apply Your Conversion Rate

Conversion rate is the percentage of attendees who hear your pitch and buy. For a $1,000 offer to a warm, qualified audience, a realistic benchmark is 5–10%. If you’re newer, use 5%. If you’ve run this webinar before with good results, use 8–10%.

For our example, let’s use 8%.

50 sales ÷ 8% = 625 attendees who need to be present for the pitch.

Quick note: conversion rate is the metric most influenced by the quality of your webinar your content, your offer, and how well you handle objections before the sales section even begins. It’s the variable with the highest ceiling for improvement if you’re willing to do the work on structure.

Step 5 Adjust for Stay Rate

Not everyone who shows up to your webinar stays until you pitch. People drop off. Life happens. The benchmark to aim for is 75% stay rate meaning 75% of your initial live audience is still watching when you make the offer.

If you need 625 people to hear the pitch, and only 75% of your audience will make it that far:

625 ÷ 75% = 833 initial attendees needed at the start of the webinar.

Stay rate is a direct signal on one thing: how engaging your presentation is. If your stay rate is below 50%, the content section of your webinar needs work it’s losing people before you ever get to the offer.

Step 6 Factor In Your Show-Up Rate

Show-up rate is the percentage of people who registered who actually attend live. The benchmark for live webinars is 20–30%. We use 25% as a standard planning number.

If 25% of your registrants show up, and you need 833 people in the room:

833 ÷ 25% = 3,332 registrants.

That’s your target. To hit $50,000 in revenue from a $1,000 offer, using realistic industry benchmarks, you need approximately 3,300 people to register for your webinar.

Show-up rate is one of the most underestimated levers in the entire funnel. The gap between registration and attendance is where most revenue quietly disappears. Your pre-webinar email sequence is the tool that closes that gap if you want a breakdown of exactly what to send between sign-up and show time, this is required reading: The Pre-Webinar Email Sequence That Doubles Your Show-Up Rate.

A Worked Example: $50,000 in Revenue

Let’s put the whole chain together so you can see it as one clean picture.

Revenue goal: $50,000
Price: $1,000
Sales needed: 50
Conversion rate: 8%
Attendees needed for pitch: 625
Stay rate: 75%
Initial attendees needed: 833
Show-up rate: 25%
Registrants needed: ~3,300

Now ask yourself: do I have enough audience, ad budget, or traffic sources to generate 3,300 registrants? If yes great, build the webinar. If no you have three options: lower your revenue goal for this launch, adjust your price, or get to work on building your audience before the launch date.

The math doesn’t lie. And it’s far better to know this now than after three weeks of production work.

The Levers That Change Everything

Here’s what I want you to understand: these aren’t fixed numbers. Every variable in this formula is a lever you can pull. And some levers are much more powerful than others.

Conversion rate is the highest-upside lever. Going from 5% to 10% cuts your registrant requirement in half. That’s the difference between needing 3,300 people and needing 1,650. Conversion rate is almost entirely determined by the quality of your webinar your content, your offer structure, and how well you handle objections. No traffic strategy can substitute for a weak pitch.

Price is often the most overlooked lever. Doubling your price from $1,000 to $2,000, with the same conversion rate and registrant volume, doubles your revenue. If your offer genuinely delivers transformation, pricing it correctly isn’t greed it’s respect for the result you create.

Show-up rate is the most improvable lever in the short term. The difference between a 20% show-up rate and a 35% show-up rate achievable with a tight pre-webinar email sequence, SMS reminders, and a compelling reason to attend live can reduce your registrant requirement by nearly 40%.

Stay rate is your real-time feedback mechanism. If you’re losing the room before the pitch, more registrants won’t solve the problem. The content section of your webinar needs to be tighter, more specific, and more valuable. For a full breakdown of what drives each of these metrics, see Average Webinar Show-Up Rate, Stay Rate, and Conversion Rate: 2024 Benchmarks it gives you exact numbers to benchmark against.

What to Do Once You Have Your Number

Once you know your registrant target, you have one job before launch day: reverse-engineer your traffic plan to hit that number.

If your target is 3,300 registrants and your landing page converts at 40% (a solid benchmark for a well-built registration page), you need approximately 8,250 people to land on that page. That tells you your ad spend, your organic content volume, your affiliate partner targets all of it flows from this single number.

I’m not a magician. I’m a marketer. And marketing done right is just this: a chain of measurable steps, each one feeding the next, with enough data at every stage to know what to fix when results fall short.

Run the formula before you build. Know your target before you launch. And if you’re sitting at 100 registrants when you needed 3,300 that’s not a webinar problem, that’s a traffic problem. And now you know exactly how to frame it.

The webinar math is just the beginning. If you want to understand the full system how to structure the four-part presentation, how to handle objections before the pitch, how to build a sales sequence that converts the people who didn’t buy on the day go deep into How to Run a High-Converting Webinar: The Complete System for Course Creators. That’s the full playbook.

And if you’re already generating $250K+ a year and want to push it further come work with us at Scale for Impact. That’s what we’re here for.