Rangdom

Future value from a principal, rate, term, and regular contribution

Enter the initial principal, the annual interest rate as a percentage, the term in years, and how often interest compounds (annually, semi-annually, quarterly, monthly, or daily). Add an optional regular contribution deposited at the end of each compounding period (an ordinary annuity). The periodic rate is i = rate ÷ 100 ÷ n and the number of periods is N = n × years. The final balance is P × (1 + i)^N + PMT × ((1 + i)^N − 1) ÷ i, and when the rate is 0 it is simply P + PMT × N. Total contributions is the principal plus every deposit, and total interest earned is the final balance minus total contributions. All three update live as you type, rounded to two decimal places as bare numbers.

An inline error appears instead of a result when the principal, rate, or contribution is non-numeric or negative, when the term is empty, non-numeric, zero, or negative, or when both the principal and the contribution are zero (a principal, rate, or contribution of 0 on its own is valid). This is the simple compounding formula only — inflation adjustment, tax, a separate contribution frequency, a per-period amortization or breakdown table or chart, currency symbols or conversion, and continuous compounding are out of scope.