Bonds normally pay interest, and when the bond matures, its face value is paid back to the investor. When purchasing a bond, the investor should know the bond's face value, interest rate and maturity date. The bond price will vary depending on the market interest rate. If that rate is less than the bond's interest rate, the bond will sell for more than its face value. If the market interest rate is more than the bond's interest rate, the bond will sell for less than its face value. To find the bond's market price, you need to do some calculations involving the interest payments and the bond's face value.
Things You'll Need
 Present value of $1 table
 Present value of an ordinary annuity table

Multiply the interest payments by the present value of an ordinary annuity factor, which is found on the present value of an ordinary annuity table (see Resources), to calculate the present value of interest payments. For example, a $200,000 face value bond that pays 10 percent interest semiannually will mature in five years. The current market interest rate is 16 percent. The interest payment is $200,000 times 5 percent, which equals $10,000 for 10 periods. On the present value of an annuity table, use 10 periods and 8 percent, for a factor of 6.7101. Therefore, the present value of interest payments is $10,000 times 6.7101, which equals $67,101.

Multiply the face value of the bond by the present value of $1 factor, which is found on the present value of $1 table (see Resources), to calculate the present value of the bond's face value. In our example, use 8 percent for 10 periods on the present value of $1 table, which equals 0.4632. Therefore, $200,000 times 0.4632, equals $92,640 as the present value of the bond's face value.

Add the present value of interest payments to the present value of the bond's face value to find the current market price for the bond. In our example, $67,101 plus $92,640 equals a market value of $159,741.
References
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