Bond Calculator

How the Bond Calculator works

Use this calculator to see how face value, coupon rate or coupon amount, yield, time to maturity, coupon frequency, settlement date, and day-count convention affect a fixed-coupon bond estimate. Use Present Value for a generic discounted-cash-flow check, IRR for broader cash-flow yield solves, ROI for one invested amount and one returned amount, Investment for contribution projections, and Interest for savings or loan interest scenarios.

Coupon-date price equals the present value of each coupon payment plus the present value of face value at maturity. The calculator maps coupon frequency to 1, 2, 4, or 12 payments per year, converts a coupon percent into an annual coupon amount when needed, divides that amount by frequency, rounds time to maturity times frequency into coupon periods, and discounts by annual yield divided by frequency. Yield mode keeps the bond cash flows fixed and bisects annual yield from 0 percent to 100 percent for 140 iterations until the present value matches the entered price. Settlement mode builds coupon dates backward from maturity, finds the next coupon date after settlement, uses the selected day-count label to find elapsed coupon-period fraction, discounts remaining cash flows from settlement, and reports dirty price, clean price, accrued interest, and accrued days.

Bond Calculator formula

This formula page covers the app's Bond Calculator: a fixed-rate coupon bond model that can value a bond on a coupon date, solve a yield from an entered price, or estimate dirty price, clean price, and accrued interest when the settlement date falls between coupon dates. It does not pull live bond prices, credit spreads, issuer data, tax treatment, call schedules, liquidity assumptions, or transaction costs.

Step by step

1. Map coupon frequency to payments per year: annually is 1, semiannually is 2, quarterly is 4, and monthly is 12.
2. Convert the annual coupon input into an annual coupon amount. Percent mode multiplies face value by coupon percent; amount mode uses the entered amount directly.
3. Divide annual coupon amount by coupon frequency to get the coupon payment per period.
4. Round time to maturity times coupon frequency to get the modeled coupon-period count, with at least one period.
5. Convert the annual yield percentage into a period yield by dividing by 100 and then by coupon frequency.
6. For coupon-date price mode, discount each coupon payment by the period yield and add the discounted face value at maturity.
7. If the period yield is 0, use coupon payments times periods plus face value instead of dividing by a zero rate.
8. For yield mode, hold face value, coupon payment, coupon periods, and coupon frequency constant, then bisect annual yield from 0 percent to 100 percent for 140 iterations until the present value matches the entered price.
9. For settlement pricing, build the coupon-date schedule backward from the entered maturity date and find the next coupon date after settlement.
10. Calculate accrued days from the previous coupon date to settlement and coupon-period days from the previous coupon date to the next coupon date.
11. Discount each remaining coupon or maturity cash flow from the settlement date using period number minus the elapsed coupon-period fraction.
12. Calculate accrued interest as coupon payment times accrued days divided by coupon-period days.
13. Report dirty price as the settlement-date discounted value, clean price as dirty price minus accrued interest, and bond price as dirty price in settlement mode.
14. Round displayed currency and percentage outputs after the full-precision bond pricing or yield solve.

Worked example

Default examples: coupon-date price and settlement clean price

The default coupon-date inputs use a $100 face value, 5 percent annual coupon, 6 percent yield, annual coupons, and 3 years to maturity. The settlement example uses the same bond with maturity on May 18, 2029 and settlement on May 22, 2026 under the 30/360 day-count option.

1. Percent coupon mode turns the 5 percent coupon into a $5 annual coupon amount on a $100 face value.
2. Annual coupon frequency means one coupon per year, so the coupon payment is $5 and the modeled period count is 3.
3. The 6 percent annual yield is also the period yield because frequency is annual.
4. Coupon-date price discounts $5 in year 1, $5 in year 2, and $105 in year 3 at 6 percent, then rounds the present value to $97.33.
5. In yield mode, entering a $97.327 price with the same cash flows solves back to a 6.00 percent yield to maturity after rounding.
6. For settlement pricing, the previous coupon date is May 18, 2026 and the settlement date is May 22, 2026.
7. The 30/360 day count gives 4 accrued days out of a 360-day coupon period, so accrued interest is about $0.0556 and displays as $0.06.
8. Discounting the remaining cash flows from the settlement date gives a dirty price of $97.39 after rounding.
9. Clean price subtracts accrued interest from dirty price and displays as $97.33.

The coupon date view explains the bond's discounted cash-flow value. The settlement view explains why the amount paid between coupon dates can differ from the clean quoted price because accrued interest is added separately.

Assumptions and what this calculator ignores

Geographic scope: works globally. The math is currency-agnostic, so enter amounts in your own currency; local taxes, fees, and product rules are not included.

• The model is for a fixed-rate coupon bond with one face value, one coupon schedule, and one maturity date. It does not model floating-rate bonds, inflation-linked bonds, amortizing bonds, structured notes, preferred shares, bond funds, issuer-specific credit spreads, default probability, liquidity, bid-ask spread, commissions, markups, call options, put options, sinking funds, or transaction costs.
• Coupon-date mode uses time to maturity in years and rounds years times coupon frequency into coupon periods. Settlement mode uses the entered maturity and settlement dates, treats 30/360 with the app's 30-day month rule, and treats actual-360, actual-365, and actual-actual as actual elapsed days in this implementation rather than a complete market-standard engine for every security.
• Scoped independent comparator checks are scoped to coupon-date price, coupon-date yield solve, and settlement dirty, clean, accrued-interest, and accrued-day outputs. Results are educational estimates from entered assumptions, not live quotes, promised returns, issuer valuations, tax results, legal determinations, trading instructions, suitability analysis, product recommendations, or financial, tax, legal, lending, investment, pension, or regulated advice.

What this formula does not include

• The calculator models fixed-rate coupon bonds only. It does not model floating-rate bonds, inflation-linked bonds, amortizing bonds, structured notes, preferred shares, or bond funds.
• No call option, put option, sinking fund, make-whole provision, conversion feature, covenant, default probability, recovery rate, credit spread, or issuer-specific risk is modeled.
• No live market price, broker quote, bid-ask spread, liquidity adjustment, commission, markup, accrued-tax treatment, withholding tax, inflation adjustment, or settlement calendar rule is pulled into the estimate.
• Yield to maturity is a solved discount rate from the entered cash flows and price. It is not a promised return, current yield, yield to worst, yield to call, taxable-equivalent yield, or personalized investment recommendation.
• Settlement pricing uses the entered coupon schedule and selected day-count label. Non-30/360 options are educational actual-day approximations in this implementation, not a full market-standard engine for every bond type.
• Scoped independent comparator checks currently pass 4 of 4 scoped fixtures for coupon-date price, coupon-date yield solving, and 30/360 settlement dirty, clean, accrued-interest, and accrued-days outputs.
• Investor.gov and FINRA source notes are used for bond terminology, price-yield relationship, fixed-coupon context, and accrued-interest convention context. They are not a claim that this app's generic present-value implementation is an official regulatory formula.
• The result is an educational estimate from the entered assumptions, not investment, tax, legal, lending, pension, regulatory, or personalised financial advice.

Common mistakes to avoid

• Confusing coupon rate with yield to maturity. Coupon is the stated payment rate or amount, while yield changes with price and the timing of the bond cash flows.
• Mixing up clean price and dirty price. Settlement mode reports dirty price as the amount including accrued interest and clean price as dirty price minus accrued interest.
• Reading the estimate as a market quote, provider statement, certain outcome, tax answer, or instruction to buy, sell, hold, or choose a bond. Real bonds can include credit risk, liquidity risk, call features, taxes, fees, settlement calendars, and issuer-specific terms.

Key terms

Yield to maturity

The annual discount rate that makes the modeled coupon and face-value cash flows equal the entered price. It is solved from the simplified cash-flow model and is not a promised or personalized return.

Clean price

The settlement price after subtracting accrued interest. It helps separate the quoted bond value from interest earned between coupon dates.

Dirty price

The settlement price including accrued interest. In settlement mode, this is the app's bond price output because it includes the accrued-interest layer.

Frequently asked questions

Methodology, sources, and disclaimer

This calculator is an original fixed-coupon bond model covering coupon-date pricing, yield solves from an entered price, and settlement-date dirty price, clean price, and accrued interest under selectable day-count conventions, validated by deterministic fixtures. It is not copied from a single source.

Fixtures pin the default 3-year 5-percent-coupon pricing example, the yield-solve inverse, and 30/360 versus actual day-count accrual. The result remains an educational estimate, not a market quote or broker pricing.

Formula version 2026.05.22-generic-bond. The version marks the calculation logic and validation fixture set used for this estimate.

• Investor.gov and SEC investor education should be used before copy discusses bond terms, fixed-coupon context, price-yield relationship, yield-to-maturity context, default risk, interest-rate risk, inflation risk, liquidity risk, call risk, prospectuses, EDGAR, bond funds, or issuer-specific risk.
• FINRA Rule 11620 and FINRA Accrued Interest Calculator should be used before copy discusses 360-day accrued-interest conventions, corporate, municipal, or government bond accrued interest, and settlement-interest context.
• MSRB materials, TreasuryDirect, issuer filings, prospectuses, broker/dealer disclosures, tax authorities, accounting standards, legal sources, and local regulators should be used before copy discusses municipal bonds, Treasury securities, tax treatment, quote conventions, settlement calendars, trading instructions, accounting treatment, legal claims, product-specific terms, or jurisdiction-specific claims.

Results are educational estimates, not advice. Read the full disclaimer.

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