compound interest

Interest computed on the original principal plus any accrued interest. Thus if 5% is the rate of interest per year and the principal is $1000, the compound amount after one year will be $1050, after two years it will be $1050 × 0.05 = $1102.50, after three years it will be $1102.50 × 0.05 = $1157.63, and so forth. Mathematically, if P is the original principal and I the rate of interest expressed as a decimal, the compound amount at the end of the n th year will be P (1 + I ) ⁿ. The growth of the compound amount is exponential and not linear.

Compare simple interest