# Future Value Calculator

> Computes the future value of a present lump sum and, optionally, of a level payment made every compounding period (ordinary annuity or annuity due) at a constant rate.

- Calculator id: `future-value` · Category: Finance (`finance`) · Tool name: `calculate_future_value`
- Canonical page: https://tttkmbb.com/finance/future-value · This document: https://tttkmbb.com/finance/future-value.md · JSON definition: https://tttkmbb.com/finance/future-value.json

## Purpose

Computes the future value of a present lump sum and, optionally, of a level payment made every compounding period (ordinary annuity or annuity due) at a constant rate.

**Use when:** You need the textbook FV of a single amount and/or a series of equal payments, e.g. for finance coursework, retirement projections or comparing investment options.

**Do not use when:** Payments are monthly while interest compounds at another frequency (use compound-interest), or you need to discount a future amount to today (use present-value).

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `present_value` | number |  | required | Lump sum invested today (0 if only payments are made). (min 0, max 1000000000000) |
| `annual_rate_percent` | number | % | required | Nominal annual rate in percent; divided by the number of periods per year. (min 0, max 100) |
| `years` | number | years | required | Investment horizon in years. (> 0, max 200) |
| `compounding_frequency` | enum: annually \| semiannually \| quarterly \| monthly \| weekly \| daily |  | optional, default "annually" | Compounding periods per year; payments (if any) are made once per period. |
| `periodic_payment` | number |  | optional, default 0 | Equal payment made every compounding period (e.g. per month when compounding_frequency=monthly). (min 0, max 1000000000) |
| `payment_timing` | enum: end \| beginning |  | optional, default "end" | Whether payments occur at the end or the beginning of each period. |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `future_value` | number |  | Total value at the end of the horizon. |
| `future_value_of_lump_sum` | number |  | present_value × (1 + i)^n. |
| `future_value_of_payments` | number |  | Annuity part of the future value. |
| `total_paid_in` | number |  | present_value + periodic_payment × n. |
| `total_interest` | number |  | future_value − total_paid_in. |
| `number_of_periods` | number |  | n = periods per year × years. |
| `periodic_rate_percent` | number | % | i = annual rate / periods per year. |

## Formula

`i = annual_rate_percent/100 / n_per_year; n = n_per_year × years; FV = present_value × (1 + i)^n + periodic_payment × ((1 + i)^n − 1) / i × (1 + i if payment_timing = beginning); with i = 0 the annuity part is periodic_payment × n`

## Data Sources

- Investopedia – Future Value (FV): Formula and Calculation — https://www.investopedia.com/terms/f/futurevalue.asp (reference, retrieved 2026-09-23)
- Wikipedia – Future value — https://en.wikipedia.org/wiki/Future_value (reference, retrieved 2026-09-23)

Data freshness: `static`. Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output.

## API

- `GET https://tttkmbb.com/api/v1/calculate/future-value?present_value=…&annual_rate_percent=…&years=…`
- `POST https://tttkmbb.com/api/v1/calculate/future-value` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/future-value · OpenAPI operationId `calculate_future_value` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool:  `run_calculator` with `{"calculator_id": "future-value", "inputs": {…}}`

## Example

- 1,000 at 8 % for 10 years, annual compounding: inputs `{"present_value":1000,"annual_rate_percent":8,"years":10,"compounding_frequency":"annually"}` → `{"future_value":2158.92,"future_value_of_lump_sum":2158.92,"future_value_of_payments":0,"total_interest":1158.92,"number_of_periods":10}`
- 200 per month at 6 % for 5 years, no lump sum: inputs `{"present_value":0,"annual_rate_percent":6,"years":5,"compounding_frequency":"monthly","periodic_payment":200}` → `{"future_value":13954.01,"total_paid_in":12000,"total_interest":1954.01,"number_of_periods":60}`

```
GET https://tttkmbb.com/api/v1/calculate/future-value?present_value=1000&annual_rate_percent=8&years=10&compounding_frequency=annually
```

## Limitations

Payments are monthly while interest compounds at another frequency (use compound-interest), or you need to discount a future amount to today (use present-value). All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**When is an annuity due appropriate?**

When each payment is made at the start of the period (rent, lease and many savings plans). It earns one extra period of interest, so FV is multiplied by (1 + i).

**Can I use a real (inflation-adjusted) rate?**

Yes: enter the real rate and the result is in today's purchasing power. Do not mix a nominal rate with inflation-adjusted payments.

## Related

- [Present Value Calculator](https://tttkmbb.com/finance/present-value.md) — The inverse: discount a future amount to today.
- [Compound Interest Calculator](https://tttkmbb.com/finance/compound-interest.md) — Balance projection with monthly deposits at any compounding frequency.