Menu
Walk backward from a revenue target to the daily growth you actually need. Five-minute back-of-napkin model that exposes whether your plan adds up -- or whether you are off by an order of magnitude.
Install with Codex or Claude Copy this prompt, paste it into Codex, Claude, or another assistant, and let it review the skill page and install it for you.
Based on SOC occupation classification
Audit your product's path from first use to first delight ("wow moment"), then systematically optimize time, friction, and drop-off points. Walks through identifying your wow, mapping the funnel, instrumentation, blockage analysis, and targeted optimization strategies. Based on David Skok's "Time to Wow" framework.
Rank a list of ideas, initiatives, features, or life decisions by scoring 2-4 dimensions on a coarse 1-5 scale. The simplest matrix that still beats gut-feel ordering. Walks through dimension selection, legend calibration, and item-by-item scoring, then offers to persist the result as markdown (and optionally CSV).
Walk through every cost and revenue assumption in your business model using structured checklists. Surfaces hidden risks, flags unknowns, and builds a complete assumptions map.
Identify and break the biggest bottleneck in your startup using a diagnostic loop based on Goldratt's Theory of Constraints. Walk through a five-step process to find what is limiting your throughput and systematically fix it.
Self-assessment across four dimensions — Skills, Experience, Leadership, Doing Hard Things — on a 2x2 of Capability vs. Willingness. From Chapter 2 of Save Your Startup by Rick Manelius.
Break a large goal down into a connected hierarchy from decade-level vision to today's next action. Systematically chunks across seven time horizons so every daily effort connects to the bigger picture.
| name | sys:napkin-math |
| description | Walk backward from a revenue target to the daily growth you actually need. Five-minute back-of-napkin model that exposes whether your plan adds up -- or whether you are off by an order of magnitude. |
| argument-hint | [optional: revenue target or business context] |
From Save Your Startup by Rick Manelius (Chapter 4) Original framework by Rick Manelius
"The goal here isn't accuracy; it's to check whether or not you have some sense of a reasonable way to get to the target."
Most founders have a revenue goal in their head but have never walked backward through the math to see what it actually requires. The numbers are not complicated. The exercise takes five minutes. But those five minutes can reveal that your plan requires 30x more growth than you are currently generating -- and that changes everything about what you should be doing today.
"We start with the end in mind and walk backward."
I will walk you through six steps, one at a time. At each step I will ask you a question. If you do not have an exact answer, give me your best guess -- napkin math rewards honesty over precision.
This calculation can be done in five minutes and tweaked for another thirty minutes.
Let's start at the end.
I will convert this to a monthly target so we have a number to work backward from.
Example: $1M ARR = roughly $83K per month.
Now we need to know how many paying customers it takes to hit that monthly number.
I will divide your monthly target by your price to get the number of paying customers required.
Example: $83K/month at $20/month per customer = 4,150 paying customers.
Does that number feel achievable? Surprisingly large? That gut reaction is useful data.
Most products have some version of a funnel -- free trial, freemium tier, demo requests, leads. Not everyone who shows up pays.
I will multiply your required paying customers by the inverse of your conversion rate.
Example: 4,150 paying customers at a 10:1 free-to-paid ratio = 41,500 free users or trials needed.
Free users do not appear out of thin air. They come from somewhere -- social media, content, referrals, ads, word of mouth.
I will multiply again to get the total audience size required.
Example: 41,500 free users at a 2:1 reach-to-signup ratio = 83,000 followers, subscribers, or regular visitors.
This is the moment of truth.
I will compare where you are to where you need to be and calculate the gap.
Example: If you are growing at 100 free users per month but need 41,500, and you need to get there in 12 months, you need roughly 3,450 per month. That is a 34x gap.
I will be direct about what the gap means. A 2x gap is a stretch goal. A 10x gap requires a fundamentally different strategy. A 50x gap means the current plan does not work -- not with more effort, but structurally.
Now we stress-test. The beauty of napkin math is that you can adjust the inputs and instantly see what changes.
I will walk you through the most impactful levers:
We will find the combination of levers that makes the math plausible -- or we will discover that no reasonable combination works, which is equally valuable information.
Once we have your base model, I will run it through four scenarios:
The point is not to predict the future. The point is to see how sensitive your plan is to being wrong.
Let's do some napkin math. Tell me:
If you only know one of these, start there. We will fill in the rest together.
By the end, you will have:
