Bond Calculator

How to use this bond calculator

This calculator estimates the value of a conventional fixed-rate coupon bond. The first mode assumes valuation occurs exactly on a coupon payment date. It can solve for one unknown—price, face value, yield to maturity, years to maturity, or annual coupon—when the other four values are supplied. The second mode handles a trade between coupon dates and separates the quoted clean price from the dirty, or invoice, price that includes accrued interest.

Inputs for coupon-date valuation

• Solve for: choose the single value you do not know. The selected field is calculated and disabled. The result is unique only when the remaining assumptions define a sensible fixed-rate bond.
• Price: the present market value of one bond. A price below face value is a discount; a price above face value is a premium. When solving for yield, a lower price generally implies a higher yield, all else equal.
• Face value: the principal repaid at maturity and the base used for percentage coupons. Common quote conventions use 100, while many individual bonds have a $1,000 denomination.
• Yield to maturity: the nominal annual discount rate, divided by the coupon frequency for periodic discounting. It is not the same as the coupon rate or current yield. Raising the required yield normally lowers price.
• Time to maturity: the remaining years until principal repayment. The entered years must produce a whole number of payment periods for the selected frequency. Longer maturities usually increase interest-rate sensitivity.
• Annual coupon: enter either a percentage of face value or the annual dollar amount. The unit switch converts the current value rather than merely changing its label. A higher coupon raises price when yield, maturity, and face value are unchanged.
• Coupon frequency: annual, semiannual, quarterly, or monthly. The calculator divides both the nominal annual yield and annual coupon by this frequency.

Inputs for settlement between coupon dates

Enter face value, yield, annual coupon, frequency, maturity date, and settlement date. Coupon dates are counted backward from maturity, so the maturity date should match the bond's actual coupon calendar. The settlement date must precede maturity. The day-count convention determines how the elapsed part of the coupon period is measured. Under 30/360, months are standardized to 30 days. Actual/360 and Actual/365 use calendar days with fixed annual denominators. Actual/Actual compares elapsed calendar days with the actual coupon period.

What the results mean

Bond price is the sum of the present values of all remaining coupons and principal. Coupon per payment is the fixed cash interest paid each period. Current yield divides annual coupon income by price; it ignores capital gain or loss at maturity. Modified duration approximates price sensitivity to a small change in yield. A modified duration of 2.7 suggests that a one-percentage-point rise in yield would produce roughly a 2.7% price decline, before convexity and other effects.

In settlement mode, dirty price is the discounted value paid by the buyer. Accrued interest compensates the seller for the fraction of the current coupon period already earned. Clean price equals dirty price minus accrued interest and is the quote commonly used for comparison. Accrued days and the accrual fraction show how the convention affected that adjustment.

Model and formula

For a coupon-date valuation, each payment occurs at a whole-number period. Between coupon dates, the first payment is discounted for a fractional period and later payments follow at regular intervals. When yield is zero, price is simply the sum of the remaining undiscounted cash flows. When the calculator solves for yield or maturity, it uses a numerical root search and checks that the requested value is mathematically identifiable.

Reading the charts and schedule

The present-value breakdown separates coupon value from principal value. A long, low-coupon bond often derives most of its value from the maturity payment, while a high-coupon bond allocates more value to interim income. The cash-flow chart groups long schedules into readable period ranges and compares contractual amounts with discounted values. The detailed table shows every payment, its discount factor, and its contribution to price; the final row includes principal repayment.

Practical interpretation and limitations

Bond prices and yields move in opposite directions. Longer maturity and lower coupon generally increase sensitivity to changing market yields. Zero-coupon bonds have no interim coupon value, so their entire price comes from discounted principal. A price equal to face value usually occurs when coupon rate and yield are equal on a coupon date.

This model assumes fixed promised payments, no default, no call or put feature, no taxes, no transaction costs, and reinvestment conditions consistent with the stated yield. Market price can also reflect liquidity, credit quality, embedded options, and supply and demand. For background on fixed-income risks and market conventions, consult the SEC's investor bond overview, FINRA's bond resources, and TreasuryDirect's marketable securities guidance. This calculator is educational and does not provide individualized investment advice.