How to validate a business idea in 30 days without building anything

Most ideas die for one reason: nobody needed them. The post-mortems say it in almost half of all cases. The cure is cheap and boring, which is why so few founders take it: spend thirty days finding out whether anyone will pay, before you spend thirty thousand finding out they will not.

This is the plan we attach to every Full Check, written out in general form. Adapt the numbers to your idea; keep the structure.

Before day one: write the kill criteria

A test is only a test if it can fail. Before you talk to anyone, write down two or three results that would make you stop. Examples:

• Fewer than 2 of 20 target customers will put down a deposit.
• The three nearest competitors already offer this at a lower price with 4.5-star ratings.
• The licence takes more than six months or costs more than the first year's expected profit.

Put them somewhere you will see them. The hardest part of the month is honouring them when the time comes.

Week 1: ten conversations about the problem

Not about your idea. About the problem. Find ten people who match the customer in your pitch: the office workers whose car sits dirty all day, the Airbnb host washing sheets at midnight, the freelancer who dreads tax season.

Ask four questions and shut up:

1. When did this last happen to you? Walk me through it.
2. What did you do about it? What did it cost in money and time?
3. What else have you tried?
4. If this disappeared tomorrow, what would change?

You are listening for three things: how often the problem happens, how much it costs them now, and whether they have already tried to solve it. People who have never tried to fix a problem do not pay to fix it. People who have cobbled together three workarounds will.

Book the calls with a scheduling link posted where these people already are: a neighbourhood group, a trade forum, the car park itself. Twenty minutes each. Write the notes the same day.

The number for the week: how many of the ten described the problem as frequent and expensive without being led. Fewer than five is a warning.

Week 2: buy from the competition

Every idea has competitors, including "do nothing" and "do it yourself". Find the three closest and become their customer. For a local service, book it. For software, start the trial and use it for a real task. For a product, order it.

Write down, for each: the price, the time it took, what was good, what was broken, and what the one-star and three-star reviews complain about. The complaints are the market telling you where the gap is. If you cannot find a complaint that your idea fixes, your pitch is "the same but me", and that is a Pivot at best.

For local ideas, count every competitor within the realistic travel radius on Google Maps or on the Local directory for your country, with ratings and review counts. Review counts are a rough proxy for volume: a market where the top three have 800 reviews each is a market with demand and incumbents. One where nobody has 20 may have no demand at all.

The number for the week: a one-page comparison with prices and the gap you fix.

Week 3: ask for money

Put up a one-page site that describes the offer as if it existed: what you get, what it costs, when it starts. Add one action: pay a deposit, pre-order, or leave an email for the first slot. A deposit beats an email every time, because emails are free to give.

Send it to the people from week one first, then to the places they gather. For a local service, print fifty flyers and put them where the customers are. For software, post in two communities as a question, not an ad. For a product, run a small ad budget to a precise audience.

Measure the share of visitors who act. On a warm, well-targeted audience, below 2 percent is a bad sign; above 5 percent with deposits is a good one. Ten paid deposits say more than a thousand sign-ups.

The number for the week: conversion rate from visitor to deposit (or sign-up), and the number of deposits.

Week 4: price the first ninety days and decide

Now list what it costs to run the idea for three months: rent or tooling, licences, insurance, equipment, your own time at a modest hourly rate, and the marketing that produced week three's results. Compare it with what week three suggests you can earn.

Then open the kill criteria and read them aloud. If a criterion was met, stop or pivot; the month has saved you a year. If none were met and the numbers work, you have the rare thing: an idea with evidence.

The number for the week: a written go, pivot or no-go, with the figures that decided it.

What this plan does not do

It does not prove the idea will succeed. It removes the ideas that were going to fail anyway, which is most of them. Founders who run the month end up with one of three things: a dead idea and their savings intact, a sharper idea aimed at the customers who actually paid, or a small business that already has customers on the day it opens. All three beat the fourth option.

If you want the month written for your specific idea, with competitors named, costs estimated for your city and the kill criteria filled in, that is what the Full Check does.