About the Accrued Interest Calculator
This accrued interest calculator finds the interest that has built up on a loan, note or bond between two dates but has not yet been paid. Enter the principal or face value, the annual interest (coupon) rate, the start date (the issue date or last payment date) and the end date (the period-end or settlement date), then choose the day-count convention your contract uses.
Accountants use it to book month-end and year-end interest accruals — the adjusting journal entry that debits interest receivable or expense and credits interest income or payable. Bond buyers use it because the purchaser pays the seller the coupon interest accrued since the last coupon date on top of the clean price.
Five conventions are supported: 30/360 US (bond basis, common for US corporate and municipal bonds), 30E/360 (Eurobond basis), Actual/360 (money markets and many commercial loans), Actual/365 Fixed (sterling money markets and many loans) and Actual/Actual ICMA (government bonds), which needs the next coupon date and the payment frequency. The table compares all of them for the same dates.
With the default inputs, the accrued interest is $1,266.67. Change any value above to recalculate instantly.
How to use the accrued interest calculator
- 1Enter the principal or face value and the annual interest rate.
- 2Enter the start date — the issue date or the last interest payment date.
- 3Enter the end date — your period-end or the bond settlement date.
- 4Pick the day-count convention from your loan agreement or bond prospectus.
- 5For Actual/Actual, add the next coupon date and the payment frequency.
Formula and method
Interest accrues in proportion to time. The day-count fraction depends on the convention. 30/360 treats every month as 30 days: days = 360(Y2−Y1) + 30(M2−M1) + (D2−D1), where under the US rule D1 = 31 becomes 30 and D2 = 31 becomes 30 only if D1 is 30 or 31; under 30E/360 any 31st becomes 30. The fraction is days ÷ 360.
Actual/360 and Actual/365 use the real number of calendar days divided by 360 or 365. Actual/Actual (ICMA) divides actual days by the number of coupons per year times the actual days in the current coupon period, so each full coupon period accrues exactly one coupon. The start date counts and the end date does not. The US 30/360 end-of-February adjustment used by some agreements is not applied.
- Principal
- Loan balance or bond face (par) value
- Annual rate
- Nominal yearly interest or coupon rate
- Day-count fraction
- Portion of a year elapsed under the chosen convention
Worked examples
$100,000 at 6%, 15 Jan to 31 Mar, 30/360
Under 30/360 US the end day 31 stays 31 because the start day is 15, so days = 30 × 2 + (31 − 15) = 76. Accrued interest is $100,000 × 6% × 76/360 = $1,266.67. The actual calendar count is 75 days.
Same loan on Actual/360 and Actual/365
75 actual days × ($100,000 × 6% ÷ 360 = $16.67 a day) = $1,250. On Actual/365 it would be $100,000 × 6% × 75/365 = $1,232.88.
Bond trade, Actual/Actual semi-annual
The coupon period from 1 March to 1 September has 184 days, and 101 days have passed. Accrued interest is $50,000 × 4.5% × 101 ÷ (2 × 184) = $617.53, which the buyer pays the seller on top of the clean price.
Frequently asked questions
What is accrued interest?+
Accrued interest is interest that has been earned (or incurred) but not yet received (or paid). Under accrual accounting it is recorded at period-end with an adjusting entry so income and expenses land in the right period.
Which day-count convention should I use?+
Use the one in your contract. US corporate and municipal bonds typically use 30/360, US Treasuries Actual/Actual, money-market instruments and many bank loans Actual/360, and many UK and Commonwealth loans Actual/365 Fixed.
Why does Actual/360 give more interest?+
Because the actual number of days is divided by only 360, a full year accrues 365/360 of the stated rate — about 1.4% more interest than Actual/365 on the same rate.
Why does a bond buyer pay accrued interest?+
The next coupon goes in full to whoever holds the bond on the record date. The buyer compensates the seller for the days the seller held it since the last coupon, so the price paid (dirty price) is clean price plus accrued interest.
How do I record accrued interest in the books?+
A lender debits interest receivable and credits interest income; a borrower debits interest expense and credits interest payable. When the cash payment arrives, the receivable or payable is cleared.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.