以下のガイドはまだ日本語に翻訳されていないため、英語で表示しています。計算機自体はすべて日本語に対応しています。
この計算機の使い方
- Enter the present value, the amount you have today.
- Enter the interest rate per period and the number of periods. For monthly periods, divide an annual rate by 12.
- Optionally enter a payment added each period, and whether it is made at the start (annuity due) or end (ordinary annuity) of each period.
計算式
The future value combines the growth of the lump sum and the future value of an annuity. For payments at the start of each period, the annuity part is multiplied by (1 + i).
FV = PV × (1 + i)^n + PMT × ((1 + i)^n − 1) / i
FV (annuity due) = PV × (1 + i)^n + PMT × ((1 + i)^n − 1) / i × (1 + i)
Example
- PV = $10,000, i = 6% per period, n = 10, no payments.
- FV = 10,000 × 1.06^10 = 10,000 × 1.790848 ≈ $17,908.48.
よくある質問
What is the time value of money?
Money available now is worth more than the same amount later, because it can earn interest. Future value measures what today's money grows to.
How do I handle monthly compounding?
Use the monthly rate (annual rate ÷ 12) and the number of months as periods, for example 0.5% for 120 periods instead of 6% for 10.
Can the rate be negative?
Yes. Negative rates are allowed for scenarios such as real (inflation-adjusted) returns below zero.