Reply To: How can I use AI to build simple ROI calculators and business cases?

Nice start — wanting a simple, practical ROI calculator is a great, focused goal. That clarity will make the tool useful right away.

Here’s a straightforward, non-jargon plan you can follow, step by step, and a few ways to ask an AI to help without copying in a long prompt.

What you’ll need

• Key inputs: current annual cost (or baseline), expected savings or additional revenue per period, implementation cost, useful life or timeframe (months/years), and an estimated adoption rate or utilization.
• A place to build it: a simple spreadsheet (Excel or Google Sheets) is ideal. Optionally a one-page slide for a business case summary.
• Basic assumptions documented: sources, ranges (low/likely/high), and who owns each assumption.

How to build it

1. List the inputs in a clear table with units (e.g., $/year, people-hours, %).
2. Choose the simple formula first: ROI = (Total benefit over period − Total cost) ÷ Total cost. For more accuracy, use NPV/discounting for multi-year cases.
3. Translate benefits into dollars (time saved × loaded hourly rate, fewer errors × cost per error, new sales × margin).
4. Add rows for one-time costs (implementation) and recurring costs (subscription, maintenance).
5. Build scenario rows: low / likely / high. Add a simple payback row: time until cumulative benefits exceed costs.
6. Validate numbers with a colleague, then write a 3‑bullet summary: expected ROI, payback period, main risk/assumption.

How an AI can help (three short ways to ask)

• Ask the AI to suggest a short list of missing inputs and reasonable default ranges for your industry (so you don’t forget hidden costs).
• Ask it to produce the spreadsheet formulas (e.g., instructions for cells) for ROI, NPV, and payback, then paste those into your sheet and check the results.
• Ask for a concise one‑page business-case summary that highlights the headline ROI, payback, and top 3 risks — ready for non‑financial stakeholders.

What to expect

• The AI will give drafts: formulas, a sample table layout, and a plain-English summary. You’ll need to verify assumptions and unit consistency.
• Common pitfalls: mixing annual vs. monthly figures, not including implementation or training time, and over-optimistic adoption rates. Use ranges and sensitivity checks.

Quick tip: start with a single use case and one realistic scenario, get feedback, then expand. Would you like guidance tailored for Excel/Google Sheets formulas or a plain-language one-page business case?