Effective annual interest rate


Effective annual interest rate

An annual measure of the time value of money that fully reflects the effects of compounding.

Effective Interest Rate

The interest rate on a debt or debt security that takes into account the effects of compounding. For example, if one has a fixed-income investment such as certificate of deposit that pays 3% in interest each month, the effective interest rate is more than 3% because compounding the interest results in a (slightly) greater principal each month on which the interest rate is calculated. In this example, the effective interest rate is calculated thus:

Effective interest rate = (1 + .03/12)^12 - 1 = .0304 = 3.04%, where .03 is the simple interest rate and 12 is the number of times in a year interest is compounded. It is also known as the annual effective rate or the annual equivalent rate. See also: Stated annual interest rate, annual percentage yield.