Track interest as it builds, not just when cash changes hands.
Accrued interest is interest that has accumulated over time but has not yet been paid or settled. For a borrower, it can be an amount owed in addition to principal. For a bond investor, it can represent interest earned between coupon payments.
The calculation depends on the product’s balance, rate, dates, and day-count rules. Understanding those inputs helps explain why a loan payoff differs from its principal balance or a bond purchase costs more than its quoted price.
What Does Accrued Interest Mean?
Interest can build before a scheduled payment date. “Accrued” describes that timing; it does not necessarily mean overdue, compounded, or capitalized.
| Context | What is accumulating? | Why it matters |
|---|---|---|
| Loan | Interest owed under the loan terms | Payments and payoff amounts may include it |
| Coupon-paying bond | Interest since the relevant coupon date | It can be added to the settlement price |
| Deposit account | Interest earned before crediting | Accrual and posting dates can differ |
Accrued interest is different from principal. Principal is the underlying amount borrowed or invested, while interest is the charge or income associated with that amount. In accounting, recognition also depends on the accounting method; a statement balance and a financial-reporting entry need not answer the same question.
How to Calculate Accrued Interest on a Simple-Interest Loan
For an illustrative daily simple-interest calculation, multiply the outstanding principal by the annual interest rate, divide by the contract’s days-per-year basis, then multiply by the number of accrual days.
Assume a $12,000 balance at 6% annual interest, using a 365-day basis, with no payments or rate changes over 30 days:
- Annual interest at that unchanged balance is $720.
- Dividing $720 by 365 gives approximately $1.9726 per day.
- Multiplying that daily amount by 30 gives approximately $59.18.
Keep extra decimal places until the final rounding step. This is a hypothetical example, not a calculation for every lender. A 360-day basis, leap-year treatment, changing principal, or other contractual rules can produce a different result.
Federal Student Aid’s interest guidance explains daily accrual and capitalization for federal student loans. The applicable loan type and repayment situation determine the actual treatment.
Why Bond Buyers May Pay Accrued Interest
When a coupon-paying bond changes hands between payment dates, settlement commonly includes an amount for interest accumulated during the seller’s holding period. The buyer may later receive the scheduled coupon, which includes interest relating to time before the buyer owned the bond.
FINRA’s accrued-interest calculator distinguishes corporate and municipal bonds from government bonds and uses the relevant bond type, dates, coupon rate, and par value. Confirm the settlement date and applicable convention instead of counting calendar days without checking the terms.
A Bond Example Using an Assumed 30/360 Convention
Suppose a bond has $10,000 face value, a 4.8% annual coupon, and semiannual payments. Each regular six-month coupon is $240. Assume the applicable 30/360 convention counts 60 days since the previous coupon date within a 180-day coupon period.
The elapsed portion is one-third of the period. One-third of $240 is $80 of accrued interest. If the clean price is 99% of face value, the clean-price amount is $9,900. Adding $80 produces a $9,980 full price before fees.
This example assumes a regular coupon period. Actual/actual conventions, irregular first coupons, floating rates, and special trading terms require the appropriate method.
Clean Price vs. Dirty Price
The clean price excludes accrued coupon interest. The dirty price, also called the full price, includes it. Fees and other charges can still affect the final settlement amount.
| Illustrative component | Amount |
|---|---|
| Clean-price amount | $9,900 |
| Accrued interest | $80 |
| Full price before fees | $9,980 |
Do not confuse accrued interest with a bond premium or discount. The interest allocation and the market price relative to face value are separate components. Our comparison of yield to maturity and coupon rate explains why the coupon alone does not describe your investment return.
Accrued interest can arise with Treasury purchases too. TreasuryDirect’s buying guide notes that some purchases, including reopened securities, can require it. Not every Treasury product follows a regular coupon-bond model.
Accrued Interest vs. Capitalized Interest
Accrual means interest builds. Capitalization means unpaid interest is added to principal. When interest is then calculated on the larger principal, future interest charges can increase.
For example, if an eligible capitalization event adds $300 of unpaid interest to a $12,000 principal balance, the new principal is $12,300. At an unchanged 6% annual rate and a 365-day basis, daily interest would rise from about $1.97 to about $2.02.
Capitalization is not automatic merely because interest accrued. Federal Student Aid’s loan-type overview describes circumstances in which unpaid interest can capitalize. Check current rules for your specific loan.
Our guide to simple and compound interest provides further context for interest calculated on principal versus interest that also reflects prior interest.
Why a Payoff Quote Can Exceed the Principal Balance
A loan’s principal balance may exclude unpaid accrued interest and other applicable amounts. A payoff quote normally identifies what must be paid by a particular date.
Edfinancial’s payoff guidance explains how daily accrual affects payoff amounts and why mailed payments may include estimated additional interest. Ask your servicer for the correct date and payment instructions.
If you are considering paying off a car loan early, review the actual payoff quote and any contract provisions rather than sending only the principal balance shown on a statement.
Tax Reporting Is a Separate Question
Accrued interest does not by itself determine when an amount is taxable or deductible. The product, tax rules, and taxpayer’s circumstances matter.
The IRS Schedule B instructions address accrued interest paid to a bond seller and the purchaser’s reporting treatment. Keep the trade confirmation and tax forms so that interest associated with the seller’s holding period is identified correctly.
For other debt instruments, discount and noncash accrual rules may also matter. Ask a qualified tax professional about the actual security or loan instead of treating every interest accrual as the same tax event.
Common Calculation Mistakes
- Using the purchase price where the bond calculation requires face value.
- Using the original loan balance after principal has changed.
- Confusing a coupon rate with yield to maturity or a loan rate with APR.
- Assuming every product uses 365 days.
- Counting from the wrong coupon or settlement date.
- Rounding daily interest too early.
- Assuming accrued interest has already been capitalized.
Frequently Asked Questions
Is accrued interest the same as overdue interest?
No. Interest can accrue normally before its payment date. Overdue interest concerns an amount that was due but not paid.
Does accrued interest change every day?
For a daily-accrual product, it generally changes with elapsed days, subject to payments, rate changes, and the contract. Other products have different conventions.
Is accrued interest an extra bond fee?
It is normally an allocation of coupon interest between owners, rather than a brokerage fee. Check the trade confirmation for both accrued interest and separate charges.
Can I use one calculation for all bonds and loans?
No. Identify the product’s balance or face value, rate, relevant dates, and day-count convention first. Verify the result against the issuer’s or servicer’s records.
Start With the Product’s Terms
Accrued interest explains what builds between payments, but the correct amount depends on the contract. Use the right balance, rate, dates, and convention, then distinguish accrued interest from principal, capitalization, market price, and fees.
This article provides general U.S. educational information, not personalized investment, tax, or borrowing advice. Examples are hypothetical; your contract and applicable rules determine the actual amount.