Draft a simple cash flow forecast
A practical way to use AI for this job in a small business, with a prompt you can copy.
You've got money in the bank today, but you're not sure if you'll have enough when the BAS, super and that big supplier bill land in the same month.
The prompt
Help me build a simple 12-week cash flow forecast in a spreadsheet. Starting balance: [amount]. Regular income: [list]. Regular costs: [list]. One-off costs: [list with dates]. Give me the column layout and formulas.
Replace everything in [square brackets] with your own details. Don't paste in anything you wouldn't want stored by the AI provider.
Steps
- Gather real numbers.
- Run the prompt.
- Build the sheet and check formulas with a simple example.
- Update it weekly.
A worked example
A Sunshine Coast landscaping business owner asks ChatGPT to help build a 13-week cash flow forecast in Google Sheets. He lists expected income (current jobs, average weekly sales), regular costs (wages, vehicle, fuel, materials), and big dates: quarterly BAS, super guarantee payments, insurance renewal.
The sheet shows week 9 dips below zero when the BAS and insurance hit together. He now knows to chase two big invoices early and move a materials order. No surprises.
Where it goes wrong
AI formulas sometimes have errors, such as a total that skips a row or a GST calculation that's off. Test the sheet with simple numbers first. And the forecast is only as good as your estimates; be honest, not hopeful.
Time saved
Building a simple forecast takes 2 to 3 hours the first time. With AI's help on structure and formulas, about an hour. Updating weekly takes 10 minutes. These are my estimates for a typical small business, not measured results.
What it costs (AUD)
Google Sheets is free, and Excel comes with Microsoft 365. Xero includes a 90-day cash flow forecast on Comprehensive (A$107 a month) and 180 days on the Ultimate plans, AUD, October 2026.
The free plans of ChatGPT, Claude and Gemini handle this fine. If you end up using AI every day, the paid plans are roughly: ChatGPT Plus approx. A$30 a month, Claude Pro approx. A$29 a month billed monthly (US$20, or about A$24 a month if you pay yearly), and Google AI Pro approx. A$33 a month through the App Store. Prices approx., October 2026. Some are billed in US dollars, so your bank may add a foreign transaction fee. Check the vendor's pricing page before you buy.
Australian notes
Include GST you'll owe on your BAS, PAYG withholding and super guarantee contributions; they're the usual surprises. Check due dates with your BAS or tax agent, as agent lodgement dates can differ from the standard ATO ones.
Privacy: the Privacy Act and the Australian Privacy Principles (APPs) cover most businesses turning over more than $3 million, plus some smaller ones such as health providers. Even if you're under the threshold, treat customer details with care: strip names, phone numbers and addresses before you paste anything into an AI tool.
My verdict
Great for building the template. The numbers have to come from you.
Common questions
How far ahead should I forecast?
13 weeks (one quarter) is a common, practical horizon.
How often should I update it?
Weekly, with actual numbers replacing estimates.
Can AI predict my sales?
No. It can structure the sheet; the estimates have to come from you.
Do this today
List every big bill you know is coming in the next three months, with dates. That's the start of your forecast.
More finance use cases
- Explain your profit and loss in plain English
- Write a polite overdue invoice reminder
- Categorise expenses from a bank export
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