How to Write a Business Plan an Expert Will Take Seriously

A business plan review goes well when the plan answers three questions quickly: who pays you, why they choose you over the alternative, and whether the numbers hold together. Experts, lenders and investors read in that order, and most plans fail in the first ten minutes because the answer to one of them is missing or contradicted by the spreadsheet. This guide shows what to write, what to cut, and how to brief a consultant so the review is worth the fee.

If you are at an earlier stage and not sure the idea works at all, start with our hub on business advice online and the guide to validating a business idea. A plan is for an idea that has already survived a few conversations with customers.

What a reviewer reads first

Reviewers rarely read front to back. The usual order is:

1. The one-page summary. What you sell, to whom, at what price, how you reach them, what you need and what you will do with it.
2. The financial forecast. Specifically the revenue line, gross margin and the month cash runs lowest.
3. The assumptions page. Where did the revenue number come from?
4. Everything else, if the first three held up.

Write the plan in that order of effort. A beautiful market-analysis chapter does nothing for a plan whose forecast assumes you win 10% of a national market in year one.

Sections that matter and how long they should be

Section	Length	What it must contain
Summary	1 page	Offer, customer, price, channel, ask
Customer and problem	1 page	Who, how many, evidence they pay for this today
Offer and pricing	1 page	What they get, what it costs them, comparison to alternatives
Route to market	1 page	How the first 50 customers arrive, with cost per customer
Operations	0.5 to 1 page	What you need to deliver, who does it
Team	0.5 page	Why you, and the gaps you know about
Financials	2 pages plus appendix	Monthly for year one, quarterly after; cash, not just profit
Risks	0.5 page	Three things that could kill it and what you would do

Eight to ten pages is plenty. A reviewer who wants more will ask.

The numbers reviewers test

Expect a consultant to stress three figures in the first half hour of a business plan review:

• Revenue build. Not "£180,000 in year one" but "12 clients a month by month six at £1,250 each, from 40 enquiries at a 30% close rate". If the plan cannot show the chain from marketing activity to enquiry to sale, the revenue is a guess.
• Gross margin. What is left after the direct cost of delivering each sale. Service businesses often forget their own time; product businesses forget shipping, returns and payment fees.
• Cash low point. The month where the bank balance is lowest, and what it is. This number decides how much funding you actually need. Many founders ask for the wrong amount because they have a profit forecast but no cash forecast.

For UK figures, use the free resources on GOV.UK for registration, tax and employment costs rather than guessing. Employer National Insurance and pension contributions alone can add a meaningful percentage to a salary line that founders routinely leave out.

Red flags that lose a reviewer in minutes

• A market size quoted in billions with no path from it to your first customer.
• Growth curves that bend upwards without a corresponding rise in marketing spend or headcount.
• No competitors listed. Every business has an alternative, even if it is "do nothing".
• Prices set by cost plus a margin, with no evidence of what the customer currently pays.
• A team section listing titles but not the gap the plan depends on filling.
• Different numbers for the same thing in the summary and the spreadsheet.

The last one is the most common and the most damaging. Reconcile every figure before anyone sees the plan.

Writing the assumptions page

This is the page that turns a forecast from fiction into a model. List every input as a single line: price, conversion rate, average order, churn, delivery cost, salary, start date for each hire. Next to each, write where it came from: a customer conversation, a competitor's price list, a supplier quote, a published benchmark. Where it is a guess, say so. Reviewers respect "assumed, to be tested" far more than confidence with no source.

A useful discipline is to run the forecast at 70% of your planned revenue and see whether the business survives. If it does not, the plan needs a smaller cost base or a bigger buffer, and you have found that out for free rather than in month eight.

How to brief a consultant for a review

A 60-minute session is the right length for a first business plan review. To get value from it:

1. Send the plan and the spreadsheet at least a day ahead, as separate files. Say which stage you are at (pre-launch, trading, raising).
2. State the purpose. A plan for a bank loan is judged differently from one for your own use or for an equity investor.
3. List your three biggest doubts. Reviewers find more when told where to dig.
4. Ask for a written list of the five changes that would most improve the plan, in priority order.

If funding is the goal, our guide to startup funding advice explains what each type of funder weighs most heavily, which should shape how you write.

After the review

Most first reviews produce the same three outcomes: the revenue build needs evidence, the cash forecast needs to exist, and the plan needs to be shorter. Expect to rewrite, not to polish. A second shorter session two or three weeks later, once the changes are made, is usually more valuable than a longer first one.

Next step

Write the summary, the forecast and the assumptions page first and make them agree with each other. Then book a business plan review with a consultant who has read plans in your sector, and bring your doubts as well as your numbers. Start with the business advice online hub to find the right specialist, and create a free ConsultChat account to arrange a session before you send the plan to anyone who can say no.