When a bond trades between coupon dates, the buyer pays the seller the interest earned so far. Enter the coupon, the coupon dates and the settlement date to get the accrued interest under any common day-count convention, and convert between clean and dirty price.
Last updated:
Bond
$
%
Dates
Leave empty to use last coupon + one period.
Price (optional)
e.g. 98.75 = 98.75% of par.
Enter your values to see the result.
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How to use the Bond Accrued Interest Calculator
Enter the face amount and annual coupon rate, and the coupon frequency.
Pick the day-count convention used by the bond (30/360 for most US corporates, Actual/Actual for Treasuries).
Enter the last coupon date and the settlement date. Add the next coupon date if it is irregular; otherwise it is calculated.
Optionally enter the clean or dirty price quote per 100 of face to convert between them.
Read the accrued interest and compare conventions in the table below the result.
Accrued interest formulas by day-count convention
Convention
Accrued interest
Typical use
30/360 US (bond basis)
Face × rate × 30/360 days ÷ 360
US corporate, agency and municipal bonds
30E/360
Face × rate × 30E/360 days ÷ 360
Eurobonds and many European issues
Actual/Actual (ICMA)
Coupon × actual days accrued ÷ actual days in period
US Treasury notes and bonds, many government bonds
Actual/360
Face × rate × actual days ÷ 360
Money-market instruments, floating-rate notes
Actual/365 Fixed
Face × rate × actual days ÷ 365
Some sterling and money-market instruments
Worked example
10,000 face of a 4.5% semi-annual corporate bond. Last coupon May 15, 2026, settlement August 20, 2026, next coupon November 15, 2026.
Actual/Actual: 97 actual days out of 184 in the period. Accrued = 225 × 97 ÷ 184 = 118.61.
Actual/360: 10,000 × 0.045 × 97 ÷ 360 = 121.25.
At a clean price of 98.75, the 30/360 accrued interest adds 1.1875 per 100, so the dirty price is 99.9375 and the buyer pays 9,993.75.
Tips
Use settlement date, not trade date. Interest accrues up to the settlement date (usually T+1 for US corporates and Treasuries).
Interest accrues from the last coupon date up to, but not including, settlement. The calculator counts days from the last coupon date to settlement.
Odd first coupons. For a new issue with a long or short first coupon, enter the dated date as the last coupon date and the actual first coupon date as the next date.
Frequently asked questions
How is accrued interest on a bond calculated?
Accrued interest = coupon per period × (days since the last coupon ÷ days in the coupon period). With a 30/360 count this simplifies to face value × annual coupon rate × days ÷ 360. For example, 10,000 of a 4.5% bond settling 95 days (30/360) after the last coupon has accrued 10,000 × 0.045 × 95 ÷ 360 = 118.75.
What is the difference between clean price and dirty price?
The clean price is the quoted price without accrued interest. The dirty (full or invoice) price is clean price plus accrued interest and is what the buyer actually pays. Bonds are quoted clean so the price does not jump on every coupon date.
Which day-count convention should I use?
US corporate, agency and municipal bonds normally use 30/360. US Treasury notes and bonds use Actual/Actual (ICMA). Eurobonds often use 30E/360, and money-market instruments typically use Actual/360 or Actual/365. The bond's offering documents state the convention.
How does 30/360 count days?
It treats every month as 30 days and a year as 360 days: days = 360 × (Y2 − Y1) + 30 × (M2 − M1) + (D2 − D1), after changing a day 31 to 30 under the convention's rules. Under the US rule, the end date's 31 becomes 30 only if the start date is the 30th or 31st; under 30E/360 both are always capped at 30.
Who receives accrued interest?
The seller. The buyer pays the accrued interest to the seller at settlement and then receives the full next coupon from the issuer, so each side ends up with the interest for the days it owned the bond.
Does this handle ex-dividend periods or defaulted bonds?
No. Some markets have an ex-coupon period before the coupon date in which accrued interest becomes negative, and defaulted bonds trade flat with no accrued interest. The calculator covers the standard case of a performing bond settling between coupon dates.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.