🪙 儲蓄帳戶未來價值計算機

The Savings Account Future Value Calculator projects how much a savings account will be worth after a chosen number of years. It combines a one-time starting balance with regular periodic deposits and applies compound interest. It then shows your future savings, the total number of deposits made, how much you contributed without interest, and the total interest earned. The tool is currency-agnostic — the dollar signs are just labels, so the math works for any currency.

Enter your starting balance, the deposit amount, and how often you deposit (deposit frequency). Choose whether deposits land at the beginning or end of each period, set the term in years, the annual interest rate as a percent, and the compounding frequency. Press calculate to see the projected balance.

Because interest may compound at a different rate than your deposit schedule, the nominal annual rate r is first converted to an effective rate per deposit period:

where m is compounding periods per year and q is deposits per year. With n = q × t total deposits, the future value is the grown starting balance plus an annuity of deposits: The "type" flag is 1 for beginning-of-period deposits (annuity-due) and 0 for end-of-period (ordinary annuity). If the rate is zero, FV simply equals PV + PMT· n.

Starting balance 500, weekly deposits of50 (q = 52) at the beginning of each week, 10 years, 0.75% annual rate compounded daily (m = 365). Then n = 520, i ≈ 0.000144243 per week, FV ≈ 27,540.72. You contributed 500 + 50×520 =26,500, so total interest is about $1,040.72.