Appendix G

HP-80 Calculation Formulas
Unless otherwise stated: n = Number of time periods  
  i = periodic interest rate expressed as a decimal  
  PMT = payment or deposit  
  PV = present value or principal  
  FV = future value  
  I = interest amount  

Compound Interest


Add on Interest Rate to Annual Percentage Rate

r = decimal Add on rate
APR = 1200iWhere i is the solution for the above equation.

Bond Calculations

n = total number of days between purchase and maturity  
INTR = decimal coupon rate (on annual basis)  
YTM = annual yield to maturity in decimal  
Bond = bond price  
If n < 182.5