Bond Accrued Interest Calculator
Calculate the accrued interest and dirty price of a bond between coupon payment dates. Accrued interest represents the portion of the next coupon earned by the seller.
Results
What is it?
When a bond is bought or sold between coupon payment dates, the buyer must compensate the seller for the interest that has accrued since the last coupon. The "clean price" is the quoted market price without accrued interest, while the "dirty price" (or invoice price) is what the buyer actually pays: clean price plus accrued interest. This calculator assumes semi-annual coupon payments.
How to use
Enter the bond's clean (quoted) price, face value, annual coupon rate, the number of days elapsed since the last coupon payment, and the total number of days in the coupon period (typically 180 for the 30/360 convention or ~182 for actual/actual). The calculator computes the accrued interest and the total dirty price.
Example scenario
A $1,000 par bond with a 6% annual coupon (semi-annual payments) is quoted at a clean price of $985. If 45 days have elapsed since the last coupon and the coupon period is 180 days, the accrued interest is $1,000 × 6% / 2 × (45/180) = $7.50. The dirty price is $985 + $7.50 = $992.50.
Pro tip
Different markets use different day-count conventions. US Treasuries use actual/actual, US corporates use 30/360, and Eurobonds use 30/360 or actual/360. Always confirm the convention for the specific bond — using the wrong day count can cause settlement disputes.