A bond is a financial instrument issued by the government or corporations when they need to borrow money from the public on a long term basis to finance certain projects. Interest payments called coupons are typically paid out to bond holders on a regular basis while the entire loan amount called the Face or Par value is repaid at the end. The public can purchase a bond to collect the regular interests and hold the bond to the end called the maturity date to collect the principal amount. Otherwise, at any time before the maturity date, the bond holder can choose to sell the bond in the market at a market price. This spreadsheet calculates the Yield to Maturity which is the interest rate that the bond holder receives if he holds the bond to maturity. The spreadsheet distinguishes between the Annual Percentage Rate and the Effective Annual Rate. When people talk about yield to maturity, they typically refer to the Annual Percentage Rate. The Effective Annual Rate basically takes into account the effect of compounding interests of the coupons.