Cash flow forecast assumptions prompt: free ChatGPT template
Updated · By Robert Breen
Use this before a cash flow forecast goes to an owner, a partner or a lender. Every forecast rests on guesses: when customers pay, which bills come due, whether work slows in the off season. Most never get written down, so when the forecast misses, nobody can tell which guess was wrong. This prompt turns your notes into a labeled assumptions list and the questions a skeptical reader would ask. It doesn't build the forecast or predict numbers; you supply every figure.
Have a professional review it. This prompt helps you explain your own numbers, not give financial advice. Have your accountant or financial advisor review anything you will act on.
The prompt
Copy it into ChatGPT (or Claude, Gemini or Copilot) and replace every [BLANK] with your own details. It uses the four parts from Prompt Writing 101: Role, Context, Task and Format.
Role: You are a careful staff accountant reviewing the assumptions in a cash flow forecast for [CLIENT]. Context: Period: [PERIOD]. Starting cash and its source: [STARTING CASH]. My notes on money in and out: [NOTES]. What is certain, such as contracts or fixed payments: [KNOWN ITEMS]. Add no number I didn't give you. Task: List each assumption as a plain sentence with its source (or "No source given"), a rating of Firm, Likely or Guess, and one early sign it is wrong. Then give up to five questions to answer before sharing, and anything forecasts usually cover that my notes leave out, such as loan payments, taxes or owner draws. Format: A table: number, assumption, source, confidence, early warning sign. Then two short lists, "Answer before sharing" and "Possibly missing". No emoji.
Fill in the blanks
[CLIENT]- The business the forecast is for, and what it does.
[PERIOD]- The months covered, weekly or monthly.
[STARTING CASH]- The opening bank balance and the statement it came from.
[NOTES]- Your rough notes on what comes in and goes out, with sources where you know them.
[KNOWN ITEMS]- Fixed or signed items: rent, a loan, a contract.
Example, filled in
A made-up example from the free lesson Turn a Client Meeting into Action Items and a Follow-Up Email (Accounting Firms). In the client meeting lesson, made-up Millbrook Accounting reviews the third quarter for Cedar Lane Landscaping, which bought a $38,000 truck on August 12 and financed most of it through the bank. Here Tom checks the assumptions in the client's fourth-quarter cash forecast. The cash figures are made up.
Role: You are a careful staff accountant reviewing the assumptions in a cash flow forecast for Cedar Lane Landscaping, a landscaping company. Context: Period: October through December, week by week. Starting cash and its source: $41,200 in checking on October 1, from the September statement Jordan uploaded. My notes on money in and out: fall cleanup jobs bring in about what they did last October and November, then work slows in December. Grace says their two commercial customers usually pay in about 45 days. The truck loan payment starts in October, amount not confirmed. Payroll holds through November, then drops when the seasonal crew finishes. What is certain, such as contracts or fixed payments: the truck loan exists and rent is fixed. Add no number I didn't give you. Task: List each assumption as a plain sentence with its source (or "No source given"), a rating of Firm, Likely or Guess, and one early sign it is wrong. Then give up to five questions to answer before sharing, and anything forecasts usually cover that my notes leave out, such as loan payments, taxes or owner draws. Format: A table: number, assumption, source, confidence, early warning sign. Then two short lists, "Answer before sharing" and "Possibly missing". No emoji.
What a good answer looks like
- The truck loan payment rated Guess, with a question asking for the loan paperwork Jordan still owes.
- The 45-day payments sourced to Grace and rated Likely, with "commercial invoices open past 45 days" as the warning sign.
- "Same as last year" flagged as needing last year's actual numbers.
- Owner draws and estimated taxes under "Possibly missing", and no new dollar figures.
How to check it before you use it
An AI draft can sound right and still say something you never told it. Use the habit from the Reply Faster lesson: check every promise, name, date and number against what you gave it before anything goes out.
- Scan the table for any number you didn't give it, and delete it.
- Get a source for every Guess, or show a range instead of one number.
- Keep the list with the forecast. When actuals arrive, it shows which assumption missed.
- Have the responsible accountant review it before it goes to a lender.
Why this prompt works
A cash flow forecast is only as good as its weakest assumption. Written assumptions turn a later budget variance into something you can explain, and the confidence column shows the soft spots, such as slow accounts receivable.
Practice it in the free lesson
Turn a Client Meeting into Action Items and a Follow-Up Email (Accounting Firms): Turn the transcript of a client's quarterly review into the decisions, an action items table with owners and due dates, and a follow-up email to the client. You do every step yourself in a practice copy of ChatGPT, and nothing touches your real accounts.
Also useful: Prompt Writing 101: Role, Context, Task, Format
Terms used here
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