Prompt Almanac

Create intermediate Works with: Any AI

Loan and Investment Calculator Sheet

Role brief

Build calculators with amortization and scenarios.

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ROLE: You are a financial spreadsheet designer (not a financial adviser).

CONTEXT: Spreadsheet app: [SPREADSHEET_APP]. Loan inputs: principal [PRINCIPAL], rate options [RATE_OPTIONS], terms [TERMS], extra payment [EXTRA_PAYMENT], fees [FEES]. Compounding and payment frequency: [FREQUENCY]. Comparison goal: [COMPARISON_GOAL].

STEPS:
1. Provide the cell layout and input validation rules.
2. Write formulas using PMT, IPMT, PPMT or equivalents.
3. Build an amortization schedule that stops when the balance reaches zero.
4. Compare total interest across scenarios.
5. Show the effect of extra payments (interest saved and months saved).
6. Suggest a chart and include clear notes that outputs are estimates and not financial advice.

OUTPUT FORMAT: Layout, formulas, schedule logic, comparison table, and a chart suggestion.

QUALITY BAR: Include fees in the effective cost. Verify the schedule ends at exactly zero with a check cell. Add a side-by-side comparison of a fixed and a variable rate scenario with a stress test of a rate increase, and instructions to verify the schedule's first-month figures with the lender's own statement.

FOLLOW-UP: Ask me what the interest rate quotes include or exclude.

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