calculate_future_value
Calculate the future value of a single lump sum: what a present amount grows to at a given rate over a given number of periods, with compounding. Formula: FV = PV x (1 + r)^n. WHEN TO USE: Use to project what an investment or cash balance will be worth at a future date under compound growth (e.g. an invested lump sum, or a liability growing at a stated rate). WHEN NOT TO USE: Do NOT use for a series of multiple, uneven cash flows — this tool compounds a single present amount. For level periodic payment streams use the annuity tool, or when you need the required starting amount (use calculate_present_value). BEHAVIOUR: pure deterministic calculation — no side effects, no network or storage access; idempotent and non-destructive; identical inputs always produce identical outputs. Division by zero, non-finite inputs, or mathematically undefined combinations return an explicit error instead of a number. RETURNS: JSON object { future_value: number (currency), inputs }. PARAMETERS: present_value (required): Starting amount in currency units, e.g. 100000. May be negative for a liability. rate (required): Periodic rate as a decimal, e.g. 0.08 = 8% per period (never pass percentage points). Rate and periods must share frequency (annual/annual or monthly/monthly). periods (required): Number of compounding periods, e.g. 5. Must be >= 0.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| rate | Yes | Periodic rate as a decimal, e.g. 0.08 = 8% per period (never pass percentage points). Rate and periods must share frequency (annual/annual or monthly/monthly). | |
| periods | Yes | Number of compounding periods, e.g. 5. Must be >= 0. | |
| present_value | Yes | Starting amount in currency units, e.g. 100000. May be negative for a liability. |