A checklist to check business viability — by the numbers

Once you believe people want what you're offering, viability becomes a math question — and it's simpler math than most founders fear. You don't need a 40-tab model or an MBA. You need five numbers and the honesty to use real ones. If the arithmetic doesn't work on a napkin, no spreadsheet will rescue it.

The five numbers

1. Price — what one customer pays you (per sale, or per month if it recurs).
2. Cost to serve — what it costs you to deliver to that one customer.
3. Margin — price minus cost to serve. This is what's actually left to run the business.
4. Fixed costs — what you pay every month no matter what (tools, rent, your own salary).
5. Break-even — fixed costs divided by margin per customer. That's how many customers just to survive.

The number founders forget

Most people remember price and forget the cost of getting a customer in the first place — marketing, ads, sales time. A business can have a great margin per sale and still lose money if every customer costs more to acquire than they're worth. When you run the checklist, fold acquisition cost into “cost to serve,” or you'll flatter yourself into a loss.

Revenue is vanity, margin is sanity. A business lives or dies on what's left after you've served the customer.

From napkin math to a real cost picture

Inside the IdeasBuenas path there's a step that helps you map your startup costs honestly — the fixed and variable numbers that decide your break-even — so the napkin math becomes a picture you can act on. But before you model costs, it's worth confirming people want the thing at all: the free first analysis does that in minutes. Desire first, then the numbers.

Run the five numbers today. If they hold, you've got a business worth building — and a much easier conversation with anyone you ask for money.