Guides › Starting a business

Interesting idea.
Does the arithmetic close?

Almost every failed business fails the same sentence: can you acquire a customer for meaningfully less than that customer is worth, often enough, before the money runs out. Each part of it can be estimated in advance well enough to make a decision.

Short answer: A business idea makes money if a customer can be acquired for meaningfully less than the customer is worth after serving costs, often enough before cash runs out. The three numbers—acquisition cost, lifetime value after costs, and runway—can be estimated from observable prices for ads, competitor charges, rebuy rates, and time to close. Accuracy within a factor of two is enough to separate workable ideas from those execution cannot save.

The three numbers

What it costs to get one customer. What one customer pays you over their whole relationship with you, after the cost of serving them. And how long you can keep going before you need those two to balance.

None requires precision. If acquisition costs roughly fifty and a customer is worth roughly five hundred, the idea is in a good universe and the details can be wrong. If acquisition is roughly two hundred and a customer is worth roughly two hundred and twenty, no amount of execution rescues it.

How to estimate them without a crystal ball

Acquisition cost: look at what advertising actually costs in your market, or how many conversations it takes to close one sale multiplied by what your time is worth. Both are observable today.

Customer value: what competitors charge, how often the thing is rebought, and what proportion of the price survives delivery cost. If nobody currently sells anything like it, that is itself the finding worth investigating first.

What the engine actually does with this question

This question routes to Startup Genius — one of 29 engagements the platform runs. It does not produce advice in general; it produces this analysis for your business:

✓ Sizes who could realistically buy this — not the size of the industry
✓ Estimates what a customer costs to acquire and what they are worth to you
✓ Tests whether the gap between those two survives contact with reality
✓ Models the cash you need and when break-even actually arrives
✓ Names the assumptions the whole idea rests on, ranked by damage if wrong
✓ Gives the cheapest test that would prove the riskiest one false

You watch the analysis get built before you pay anything. Read a complete report here if you would rather see the depth first.

Questions people ask about this

How do I validate a business idea?

Identify the assumption that would sink it if false — usually that people will pay your price — and test only that, as cheaply as possible. A real offer made to real prospects tells you more in a week than months of research, because interest and payment are different behaviours.

What if nobody else is doing it?

Find out why before treating it as an advantage. Sometimes nobody thought of it; more often people tried and the economics did not work. An empty market is evidence, and it points in both directions equally.

How accurate do these estimates need to be?

Accurate enough to tell a good idea from a bad one, which is usually within a factor of two. Precision matters far less than order of magnitude — the ideas worth pursuing tend to be obviously good once the numbers are on paper, and the marginal ones rarely become good with better estimates.

Test the idea before it costs you anything.

Describe the situation in your own words and we will tell you which analysis answers it — before you sign up for anything.

Describe my situation →

Prefer to skip ahead? Go straight to the free diagnostic.