Bond Calculator
Price, Yield & Accrued Interest for Fixed-Rate Bonds
For bonds priced exactly on a coupon payment date. Choose the unknown value, then supply the remaining four to solve for it.
Bond Parameters
For bonds trading between coupon dates. Returns the dirty (invoice) price, clean (quoted) price, and accrued interest owed to the seller.
Bond & Trade Details
Understanding Bond Pricing
A bond is a promise: lend money today, and receive scheduled interest payments plus your principal back at a fixed future date. But a bond's price almost never equals its face value once it starts trading — it rises and falls with prevailing interest rates, time remaining, and the coupon it carries. These calculators translate that relationship into two practical tools: solving for any single unknown among a bond's core terms, and pricing a bond precisely on the date it actually changes hands.
Price Moves Opposite to Yield
When market yields rise above a bond's fixed coupon rate, its price falls below face value (a discount) to compensate new buyers. When yields fall below the coupon, the price rises above face value (a premium). A bond priced exactly at face value has a yield equal to its coupon rate.
Five Variables, One Equation
Price, face value, yield, coupon, and time to maturity are all linked by a single discounted cash flow equation. Know any four, and the fifth is fully determined — which is exactly what the first calculator above solves for.
Clean vs. Dirty Price
Bonds rarely trade exactly on a coupon date. The clean price is what gets quoted publicly; the dirty price is what the buyer actually pays, since it folds in the interest the seller has already earned but not yet received.
Day-Count Conventions Matter
The market doesn't count days the same way everywhere. Corporate bonds typically use 30/360, while U.S. Treasuries use Actual/Actual. The convention changes the accrued interest slightly — usually by fractions of a cent per $100 of face value, but it matters for settlement accuracy.
The Bond Pricing Formula
A bond's price is the present value of every future coupon payment plus the present value of the face value repaid at maturity, all discounted at the periodic market yield.
Where P is price, C is the coupon paid each period, r is the yield per period, N is the number of periods to maturity, and F is the face value.
Worked Example
- Face Value: $100
- Coupon: 5% annually
- Yield Required: 6%
- Time to Maturity: 3 years
- Price: $97.33 (a discount, since yield > coupon)
Accrued Interest & Settlement Pricing
Bond interest accrues continuously between coupon dates, but payments are only made on the coupon date itself. If you buy a bond three days after the last coupon, you owe the seller three days of interest — even though you haven't received a payment yet. That amount is the accrued interest, and it's added to the clean price to arrive at the dirty price you actually pay at settlement.
- 30/360 (Bond Basis): Assumes every month has 30 days and every year has 360 — the standard for most U.S. corporate and municipal bonds.
- Actual/360: Counts real calendar days elapsed, but still divides by a 360-day year. Common for money-market instruments.
- Actual/365: Counts real calendar days elapsed against a fixed 365-day year, used by some non-U.S. government bonds.
- Actual/Actual: Uses the true number of days in both the accrual period and the year — the convention used for U.S. Treasury securities.
Key Takeaways
- Bond prices and yields move in opposite directions: rising rates push existing bond prices down, and falling rates push them up.
- The current yield differs from yield to maturity: the yield used in these calculators reflects the return required over the life of the bond, not simply the coupon divided by today's price.
- The dirty price is what actually settles: published bond quotes almost always show the clean price, so remember to add accrued interest when comparing to what you'll actually pay.
- These tools price fixed-rate bonds only: they do not account for call provisions, credit risk, embedded options, or liquidity premiums that can move real-world market prices.