The three numbers in your plan that have to agree

A business plan almost never fails a single-number test. Each figure looks defensible on its own page. It fails a consistency test — and nobody runs that one, because running it means holding three sections in your head at once.

Here are the three numbers, and the arithmetic that has to close between them.

1. The market you claim

Not the industry. The slice you can actually reach with the channel you named. If your plan says "the U.S. home services market is $600B" and your acquisition plan is a Facebook campaign in one metro, the honest number is the households in that metro who buy this category in a year. That number is usually four orders of magnitude smaller, and the whole plan quietly depends on which one you used.

2. The price you charge

Fine on its own. The problem is that price is doing double duty: it sets your revenue, and it sets how much you're allowed to spend to acquire a customer. Founders set price against competitors and set acquisition spend against their budget, and never check that the two are compatible.

3. What a customer costs to acquire

The number people write down is the cheap one — cost per click, or cost per lead. The number that matters is cost per paying customer, which is cost per lead divided by every conversion step between the lead and the money. Four steps at 25% each is a 1-in-256 funnel. That's not pessimism; that's multiplication.

Where they collide

Put them together and one of three things is true:

Your CAC exceeds a year of revenue. At $49 a month with 70% retention through year one, a customer is worth a few hundred dollars. If acquisition costs $900, you don't have a growth problem, you have a business-model problem — and no amount of funnel optimisation closes a 3× gap.

Your market can't hold your plan. If you need 40,000 customers to hit your revenue target and the reachable segment is 60,000 households, you've written a plan that requires two-thirds market share. Say that out loud and the plan changes.

Your price contradicts your positioning. A $17 tier that promises unlimited usage of something with a real per-use cost is a promise to lose money on your best customers. Cheap and unlimited can coexist only when marginal cost is near zero — and if your product thinks for a living, it isn't.

The check nobody runs

Write these three sentences and see whether they survive next to each other:

1. "We can reach ___ potential customers through ___."
2. "They pay ___ per month and stay ___ months, so one is worth ___."
3. "Acquiring one costs ___, which is ___% of that value."

If the third number is above about 33%, you're funding growth out of capital rather than out of margin. That can be a deliberate decision. It should never be an accidental one.

The reason this check gets skipped isn't difficulty — it's that market sizing, pricing, and acquisition usually get written on different days, often by different people, and nothing forces them into the same room. That's precisely why we run acquisition before finances and feed the real CAC into the model, instead of letting each section be independently plausible.

Plausible three times over is how a plan gets funded and still fails.