There are two formulas you can use to annualize daily interest rates, either by calculating the annual percentage rate (APR) or the annual percentage yield (APY), depending on your goal.Calculating the APR based on daily interest is simple: Multiply the periodic rate by the number of periods in the year, in this case, 365. So, if the rate was 0.02%, your equation would be:APR = 0.0002 x 365 x 100 = 7.3%It's similar but more complicated for APY:APY = (1 + periodic rate)^ number of periods) – 1In our example, that would be:APY = (((1 + 0.0002)^365)) – 1) x 100 = 7.57%