The formula for compound interest is: A = P (1 + r/n)^(nt), where:
A = the future value of the investment/loan, including interest P = the principal investment amount (the initial deposit or loan amount) r = the annual interest rate (decimal) n = the number of times that interest is compounded per year t = the number of years the money is invested or borrowed for
This formula demonstrates how quickly an investment can grow when earnings are reinvested.