Build an Excel forecast, scenario and CFO memo with Claude, Copilot and ChatGPT

Our rewrite with extra checks. The poster didn't test it.

Before you start, ask me 1–3 short questions about the details below and wait for my answers. Once I've answered, confirm the plan in one line and run the whole task start to finish.

Goal: Build a 12-month forecast from my actuals, run one scenario on it and write a short memo for leadership.

Questions to ask me first:
- What does the business sell, and how many locations or segments are in the data?
- Which assumptions should drive the forecast (traffic, average ticket, costs)?
- Who reads the memo, and what decision do they need to make?

Inputs (fill in or confirm):
- Monthly actuals (revenue, cost of goods sold, operating expenses): [SHEET]
- Budget figures, if any: [SHEET]
- Scenario to test: [FOR EXAMPLE, TRAFFIC -10% AND FOOD COSTS +5%]
- Memo reader and decision: [READER / DECISION]

Rules:
- Before building, tell me your plan and wait for my OK.
- Put assumptions on their own tab and link every forecast cell to them; no hard-coded numbers.
- Include every line in the source data, including cost of goods sold.
- In the scenario, adjust costs for the lower volume first, then apply the price increase.
- Lead the memo with the finding and end with a recommendation.

Checkpoint: After the base forecast, show me the assumptions and totals before running the scenario.

If you get stuck: If the data has gaps or odd months, flag them instead of smoothing them over.

Verify before you finish: Check that the base forecast ties to the actuals and that the scenario changes flow through to profit.

Output: An assumptions tab, a monthly forecast, a scenario comparison and a one-page memo.

Done when: The model is linked, the scenario math is right and the memo is ready to send.