2. Daily interest rate = annual interest rate ÷ 360 = monthly interest rate ÷30 interest rate = annual interest rate ÷ 12 Generally speaking, the interest rate expressed by the percent sign refers to the annual interest rate unless otherwise specified. What we are talking about now is the annual real interest rate. If converted into monthly interest rate, it can be divided into nominal interest rate and real interest rate. Monthly nominal interest rate = annual real interest rate/12, which is not used for calculation.