As of 13 August 2026, AI can only partly build a financial model for your UK small business.

What to actually do

1. Hand it to a person

   The route this page recommends

   Someone with a licence or accountable authority has to sign this before it counts.

2. Use a tool built for this

   Second choice

3. Do it yourself

   The distant third

   A chat interface, power-user skill, and roughly 1 hour until you can act on the result.

   How to actually do it

   1. Open your latest bookkeeping reports, bank statements and management accounts, then gather monthly sales, direct costs, overheads, payroll, VAT payments, tax payments, debt repayments and opening cash.
   2. Separate historical actuals from forecasts and put the figures into a table with one row per month, keeping the source of each figure beside it.
   3. Write down the business decisions the model must test, such as a price change, new hire, loan, expansion or slower customer payments, without adding figures you have not decided.
   4. Paste the prompt and your tables into ChatGPT, Claude or Gemini, then ask it to produce the model layout, formulas, assumptions and three scenarios without filling any [INPUT NEEDED] fields.
   5. Create the proposed sheets in a spreadsheet and paste in the historical figures, then compare revenue, costs, payroll, tax payments and closing cash with your bookkeeping and bank records.
   6. Test the formulas with simple changes, including zero sales for a month, one additional employee and a delayed customer payment, and check that the cash and profit outputs change in the expected direction.
   7. Ask an accountant to check the tax treatment, VAT treatment, working-capital assumptions and scenario logic before using the model for borrowing, hiring or major spending decisions.

   Prompt

   Build a monthly financial model for my UK small business using the information below. Create a clear structure for revenue, direct costs, overheads, staffing, VAT where relevant, corporation tax or income tax where relevant, cash movements, opening cash, closing cash and a simple profit and loss view. Use pounds sterling and label every assumption, input and formula. Include a base case, an optimistic case and a cautious case, but do not invent figures: mark missing information as [INPUT NEEDED]. Add a break-even view and show which assumptions have the greatest effect on closing cash. Keep historical actuals separate from forecasts. State whether each tax or accounting treatment needs confirmation from an accountant, and do not give tax or investment advice. Explain the model sheet by sheet and list validation checks I should perform. Return the proposed spreadsheet layout, formulas in plain English, and a table I can paste into a spreadsheet. Business details: [business type and industry]. Forecast period: [months and start date]. Historical data: [paste monthly sales, costs, payroll and cash figures]. Planned changes: [paste hiring, pricing, borrowing, investment or expansion plans]. Known payment timings: [paste customer and supplier payment terms]. Other assumptions: [paste only assumptions I have already decided].

   Open it prefilled in ChatGPT or Claude, or copy it into Gemini, which takes no prefill link.