Bond Accrued Interest Calculator

How it is calculated

The coupon rate is entered as an annual percentage. The tool infers how often the bond pays from the coupon period length: about 365 days means annual, about 182 days semi-annual, about 91 quarterly and about 30 monthly (each within roughly 6%). For those cases accrued = face × (rate / 100) / n × (days since / period days), where n is the number of coupons per year. For any other period length it uses accrued = face × (rate / 100) × days since / 365. If you leave the period blank it assumes 365 days. Days since the last coupon cannot exceed the period by more than one day, and the period must be above zero; otherwise there is no result. The answer is a straight-line (actual-day) accrual in dollars; day-count conventions such as 30/360 can differ slightly.

Common mistakes

• Entering the per-coupon rate (for example 3% for a semi-annual 6% bond). The field expects the annual rate and divides by the payment frequency itself, so a semi-annual rate would halve the answer twice.
• Typing the days remaining until the next coupon in the "days since" field. The field counts days elapsed since the last coupon.
• Entering the whole bond life or days to maturity as the period. The period is only the length of one coupon interval, for example 182 days.
• Leaving the period empty on a semi-annual bond. It then defaults to 365 days, which treats the bond as annual-pay and gives a different figure (about $9.86 instead of $9.89 in the example).
• Entering days since that are longer than the coupon period. Anything more than one day beyond the period returns no result instead of a capped value.