将来価値計算機

Future value (FV) is the projected worth of an investment at a specific point in the future, based on a given rate of return. It matters because it helps you understand how much your savings or investments will grow over time, enabling better financial planning for goals like retirement, education, or major purchases.

An ordinary annuity makes payments at the end of each period (e.g., most bond coupon payments), while an annuity due makes payments at the beginning of each period (e.g., rent or insurance premiums). An annuity due grows slightly more because each payment has one extra period to earn interest.

More frequent compounding (monthly vs. annually) produces a higher future value because interest begins earning interest sooner. For example, $10,000 at 6% compounded monthly yields more than 6% compounded annually over the same period. The difference becomes more pronounced at higher rates and longer time horizons.

The future value of a lump sum is calculated as FV = PV x (1 + r/n)^(n*t), where PV is the present value, r is the annual interest rate, n is the number of compounding periods per year, and t is the number of years. This formula accounts for compound interest on the initial investment.

Inflation erodes purchasing power over time. A dollar today buys more than a dollar 20 years from now. Adjusting for inflation (using the real rate of return) shows your investment's future value in today's purchasing power, giving you a more realistic picture of what your money will actually be worth.

The growth multiplier shows how many times your total contributions have multiplied through compound interest. For example, a growth multiplier of 1.5x means your investment grew to 1.5 times what you put in. A multiplier above 2x means you earned more in interest than you contributed.