← IndexEntry № 202·business

Business Case for a Project With ROI and Payback

Frames a project as an investment with quantified benefits, a transparent ROI and payback calculation.

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§ When to use this

A project competes for budget against every other thing the company could do with the same money, which is why 'it would be nice to have' loses and a framed investment wins. This prompt builds a real business case: it states the problem and the cost of doing nothing, quantifies the benefits with explicit assumptions, lays out build, run, and opportunity costs, and shows a simple ROI and payback-period calculation with the math visible. Making the arithmetic transparent is what lets a CFO trust or challenge it, rather than waving it through or rejecting it on instinct. The instruction to use conservative figures from any range you give, and to label them, keeps the case credible under scrutiny; over-optimistic projections are how business cases lose believers. It also refuses to fabricate financial numbers, so the output is only as strong as the inputs you provide. Use it to justify a project to leadership or finance, or to honestly talk yourself out of a project whose payback never actually arrives.

§ The Prompt— fill in the fields, then copy or open in a tool

§ Customize0/6 fields filled

Proposed project[PROPOSED PROJECT]What you want to do, e.g. 'replace manual invoicing with an automated billing system.'

Company[COMPANY]The organization and context, e.g. 'a 120-person agency.'

Problem and cost of inaction[PROBLEM AND COST OF INACTION]The pain and what it costs to leave it, e.g. 'billing errors cause ~$8k/month in disputes and late payments.'

Revenue gains, cost savings, or time saved[REVENUE GAINS, COST SAVINGS, OR TIME SAVED]Expected benefits, e.g. 'saves 60 finance hours/month and cuts disputes 70%.'

Build, run, and opportunity costs[BUILD, RUN, AND OPPORTUNITY COSTS]All-in costs, e.g. '$25k setup, $1.2k/month software, plus 3 weeks of staff time.'

Duration[DURATION]Timeline to implement, e.g. 'two months to roll out.'

your prompt — fill the fields above

Act as a finance-literate consultant building the business case for [PROPOSED PROJECT] at [COMPANY]. Problem it solves: [PROBLEM AND COST OF INACTION]. Expected benefits: [REVENUE GAINS, COST SAVINGS, OR TIME SAVED]. Estimated costs: [BUILD, RUN, AND OPPORTUNITY COSTS]. Timeline: [DURATION]. Produce a structured case: Executive summary, Problem and cost of doing nothing, Proposed solution, Quantified benefits with stated assumptions, Costs, a simple ROI and payback-period calculation showing the math, Key risks with mitigations, and a recommendation with the decision deadline. Where I gave a range, use conservative figures and label them. Do not fabricate financial numbers I did not provide.

Open with your prompt →ChatGPT ↗Claude ↗Sends your filled-in prompt straight into a new chat.

§ Example Output

What you can expect back

Executive summary: Automating billing pays for itself in well under a year and removes a recurring source of revenue leakage. Cost of doing nothing: ~$8k/month in disputes and late payments, plus 60 finance hours/month spent on manual work. Solution: an automated billing system, live in two months. Quantified benefits [conservative]: dispute reduction of 70% saves ~$5.6k/month; 60 hours saved at ~$45/hour loaded is ~$2.7k/month; total ~$8.3k/month, ~$100k/year. Costs: $25k one-time setup, $14.4k/year software, plus ~$5k of staff implementation time. ROI year one: (~$100k benefit minus ~$44k year-one cost) / $44k cost, roughly a 127% return. Payback period: ~$30k of upfront cost recovered in about four months of net benefit. Risks: adoption lag and edge-case invoices (mitigate with a pilot on one client segment first). Recommendation: approve, with a decision by month-end to hit the timeline.

Illustrative example — your results will vary by tool and inputs.

§ Pro Tips

Get sharper results

01Always quantify the cost of doing nothing. A vivid status-quo cost is often more persuasive than the upside.
02Force conservative numbers and label them. A case that survives skepticism beats one that dazzles and then disappoints.
03Show the ROI and payback math in the open. Hidden arithmetic invites rejection; visible arithmetic invites a yes.
04Run it on a project you doubt, too. A business case that can't reach payback is a cheap way to kill a bad idea early.

§ Variations

Adapt it for your case

Three-scenario model

Ask for conservative, expected, and optimistic cases so leadership sees the range, not one point estimate.

Phased investment

Add: 'Structure it as a small pilot first with a go/no-go gate before the full spend.'

Cost-of-delay angle

Have it quantify what each month of delay costs to create urgency around the decision date.

Best For — Roles

Use For — Tasks

Tags#business-case#roi#investment

§ FAQ

Common questions

Can the AI calculate a trustworthy ROI?

Only from the numbers you supply; it won't invent financials. It does the arithmetic and shows the math so you and your finance team can verify every step.

What's the difference between ROI and payback period?

ROI is the return relative to cost, usually over a year; payback period is how long until the savings recoup the upfront spend. The prompt reports both because they answer different questions.

How conservative should my estimates be?

Lean conservative on benefits and generous on costs. A business case that holds up under a skeptical CFO's questioning is worth far more than an optimistic one that collapses on contact.

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