Bond Accrued Interest Calculator

Enter your bond's face value, coupon rate, and days since the last payment to calculate accrued interest, dirty price, and more.

Created by Luis GonzalezLast updated: June 16, 2026

How to Use This Calculator

1
Enter your bond details
Input the bond's face value (e.g., $1,000), annual coupon rate (e.g., 6%), days since the last coupon payment (e.g., 90), and total days in the coupon period (e.g., 180 for semi-annual).
2
Review your results
The calculator displays three result cards -- Accrued Interest, Dirty Price, and Accrual Progress -- plus an insights card with coupon payment, remaining interest, daily accrual, and days remaining.

Example Calculation

An investor sells a $1,000 bond with a 6% annual coupon 90 days into a 180-day semi-annual period.

Face Value of Bond

1000

Annual Coupon Rate

Days Since Last Coupon

Days in Coupon Period

180

Results

Accrued Interest

$30.00

Dirty Price

$1,030.00

Accrual Progress

50.0%

Insights card shows coupon payment of $29.

Tips

Higher Coupons Compound the Cost for Buyers

On a $10,000 bond at 8%, buying 120 days into a 180-day period means paying $533.33 in accrued interest on top of the clean price -- a $10,533.33 total dirty price. Compare that to the same bond at 4%, where accrued interest at the same point would be only $266.67.

Annual vs. Semi-Annual Periods Change Results

A $1,000 bond at 4% with 30 days elapsed shows $3.29 accrued interest on a 365-day annual period. The same bond on a 180-day semi-annual period would show $6.67 -- more than double -- because the annual coupon is spread over fewer days per period.

Settlement Dates Add Hidden Days

Accrued interest is calculated to the settlement date, not the trade date. For corporate bonds (T+1 settlement in 2026), buying a $1,000 bond at 6% means one extra day adds roughly $0.16 to your accrued interest cost. For a $5,000 bond at 5%, each extra day adds $0.68.

Late in the Period Means Near-Full Coupon Cost

Buying a $1,000 bond at 6% with 150 of 180 days elapsed means $50.00 in accrued interest -- almost the full $29.59 semi-annual coupon (which reflects a 180/365 proportional payment). You recover this when the next coupon pays out, but it ties up cash upfront.

The Bond Accrued Interest Calculator determines the portion of a coupon payment earned by the bond seller up to the settlement date. For a $1,000 bond at 6% that is 90 days into a 180-day semi-annual period, the accrued interest is $30.00, making the dirty price $1,030.00. This figure is essential for any fixed-income trade, as it ensures the seller is fairly compensated for interest earned during their holding period.

Accrued Interest Formula and Mechanics

The calculation follows a straightforward proportional method:

Accrued Interest = Face Value x (Annual Coupon Rate / 100) x (Days Since Last Coupon / Days in Coupon Period)

The Face Value is the bond's par value (typically $1,000 for corporate bonds), Annual Coupon Rate is the stated interest rate, Days Since Last Coupon is how long the seller held the bond in the current period, and Days in Coupon Period is the total cycle length (180 for semi-annual, 365 for annual).

The dirty price (what the buyer actually pays) equals the clean price plus accrued interest. For the default example: $1,000 + $30.00 = $1,030.00. The daily accrual rate is $0.1644 per day ($1,000 x 0.06 / 365).

💡 Planning your overall bond portfolio returns? Our Bond Yield Calculator can help you compare yields across different bonds.

Worked Example: Corporate Bond Sale at 5%

An investor sells a $1,000 corporate bond with a 5% annual coupon, 45 days into a 180-day semi-annual period:

Component	Calculation	Result
Accrued Interest	$1,000 x 0.05 x (45/180)	$12.50
Dirty Price	$1,000 + $12.50	$1,012.50
Full Coupon	$1,000 x 0.05 x (180/365)	$24.66
Daily Accrual	$1,000 x 0.05 / 365	$0.1370
Accrual Progress	45/180	25.0%

The buyer pays $1,012.50 total and will receive the full $24.66 coupon at the end of the period, effectively recovering $12.16 of their accrued interest payment.

💡 Understanding accrued interest is one part of bond analysis. Use our Bond Duration Calculator to measure interest rate sensitivity for your bond holdings.

When This Calculator Does Not Apply

This calculator is designed for standard fixed-rate coupon bonds. It does not apply to:

Bonds traded flat (defaulted or in arrears) -- no accrued interest is exchanged; the clean price reflects recovery expectations.
Floating-rate notes -- the coupon rate changes periodically based on benchmarks like SOFR, so a single annual rate is inaccurate.
Zero-coupon bonds -- these pay no periodic interest; the return comes from buying at a discount to face value. Use a yield-to-maturity calculation instead.

Frequently Asked Questions

How is bond accrued interest calculated?

Accrued interest uses the formula: Face Value x (Annual Coupon Rate / 100) x (Days Since Last Coupon / Days in Coupon Period). For a $1,000 bond at 6% that is 90 days into a 180-day period: $1,000 x 0.06 x (90/180) = $30.00.

What is the difference between clean price and dirty price?

Clean price is the quoted market price of a bond excluding accrued interest. Dirty price equals clean price plus accrued interest -- it is the actual amount the buyer pays. For a $1,000 face value bond at 6% with 90 days accrued in a 180-day period, the dirty price is $1,000 + $30.00 = $1,030.00.

Why is the coupon payment different from face value times the coupon rate?

The calculator computes the coupon payment for a specific period length, not a full year. The formula is Face Value x Annual Rate x (Days in Period / 365). For a $1,000 bond at 6% with a 180-day semi-annual period: $1,000 x 0.06 x (180/365) = $29.59, which is slightly less than the nominal $30 half-year amount.

How does day count convention affect accrued interest?

This calculator uses a simple proportional (actual/actual) method. U.S. Treasury bonds use actual/actual, while many corporate bonds use 30/360. On a 30/360 basis, each month is treated as 30 days regardless of actual length, which can shift the accrued interest by a few cents. For a $5,000 bond at 5% with 60 days elapsed in a 182-day period, the proportional method gives $82.42 in accrued interest.

What happens to accrued interest on the coupon payment date?

On the coupon payment date, accrued interest resets to zero. The bondholder on the record date receives the full coupon payment. If you buy a bond on the ex-coupon date or after, you pay no accrued interest because the seller keeps the upcoming coupon. Between payment dates, accrued interest grows daily -- at $0.16 per day for a $1,000 bond at 6%.

Does this calculator work for zero-coupon or floating-rate bonds?

No. Zero-coupon bonds do not pay periodic interest, so accrued interest as a separate settlement component does not apply -- the return is embedded in the price discount. For floating-rate notes, the coupon rate changes periodically (e.g., based on SOFR), making a single annual rate inaccurate. This calculator is designed for standard fixed-rate coupon bonds.