Hi I'm Jackie brainy marketing director with savings bonds com we're your bonds talk to you here's a golden rule when a bond is purchase determines how interest will be calculated bonds purchased may 1997 through april two thousand five will earn interest based on the five year treasury security yields right from the start the new rate for EE bonds will be ninety percent of the average yields on the five year treasury security for the preceding six months and will increase in value every month instead of every six months interest is compounded semi-annually these bonds will earn interest for 30 years sounds complicated it is if you try to figure it out on your own if you want to know how your bonds are performing go to ww savings bonds it's simple to get your bonds valued online and not have to worry about the formulas will deliver the information to you on a savings bond inventory report to get your free savings bond values with a complimentary color coded personalized savings bond inventory report go to ww savings bonds calm forward slash calc that's ww savings bonds calm forward slash calc.