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Bond Price Calculator

Calculate the fair market price of a bond, present value of coupon cash flows, and par value discount/premium.

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Understanding Bond Price Valuation

The price of a bond represents the present value of all future cash flows expected from the security, discounted at the current market yield to maturity (YTM). Bond cash flows consist of two elements: periodic interest (coupon) payments throughout the life of the bond and the principal (face value) repayment at maturity.

Bond Price Formula

The present value formula for a bond paying $m$ coupon payments per year is:

$$P = \sum_{t=1}^{N} \frac{C}{(1 + y_p)^t} + \frac{M}{(1 + y_p)^N}$$

where $P$ is the bond price, $C$ is the periodic coupon payment ($M \cdot r / m$), $M$ is the par value, $y_p$ is the periodic yield ($y / m$), and $N$ is total compounding periods ($n \cdot m$).

Factors Influencing Bond Prices

  • Market Interest Rates: Bond prices and interest rates move in opposite directions. When rates rise, existing bond prices drop, and when rates fall, bond prices increase.
  • Coupon Rate vs Yield: If the coupon rate exceeds the required market yield, the bond trades at a premium ($P > M$). If the coupon rate is lower than market yield, it trades at a discount ($P < M$).
  • Time to Maturity: As maturity approaches, a bond's price naturally converges toward its par value.

Frequently Asked Questions

What is the difference between clean price and dirty price?

Clean price is the quoted bond price excluding accrued interest between coupon dates. Dirty price (or full price) includes accrued interest and is the actual cash amount paid by the buyer upon settlement.

Why do bond prices fall when interest rates rise?

Newly issued bonds offer higher yield rates when interest rates rise. Existing bonds with lower fixed coupon payments become less attractive, so their market price must fall until their yield matches current market interest rates.

How does coupon frequency affect bond price?

More frequent compounding periods (e.g. semi-annual or quarterly) allow investors to receive and reinvest cash flows earlier, slightly increasing the present value of coupon cash flows.

What is a zero-coupon bond price formula?

For zero-coupon bonds, $C = 0$, so the bond price is simply the discounted face value: $P = \frac{M}{(1+y)^n}$.