Bond Calculator

How to Use Strike Money Bond Calculator?

To use the Strike Money bond calculator, follow the 5 steps below.

• Step 1: Choose the solve mode: Yield to Maturity (calculates expected annual bond return), Bond Price (computes the fair market price), Coupon Income (estimates periodic interest payments), or Accrued Interest (calculates earned but unpaid interest).
• Step 2: Enter bond details: Face value, coupon rate, coupon frequency and maturity period, based on the solve mode selected.
• Step 3: Enter bond price or yield: Enter the market price to calculate yield, or the desired yield to calculate bond price, depending on the solve mode.
• Step 4: Set the day-count convention (for Accrued Interest): Choose the method used to count days between coupon dates.
  • 30/360: Assumes 30 days per month and 360 days per year — common in corporate bonds.
  • Actual/360: Uses actual days but assumes a 360-day year — common in money market instruments.
  • Actual/365 and Actual/Actual: Use actual days and an actual (365 or 366-day) year — common in government bonds and UK securities.
• Step 5: Read the bond results: The calculator displays Yield to Maturity (YTM), current yield, bond price, coupon income, or accrued interest depending on the mode selected.

Suppose you purchase a government bond with ₹1,000 face value, 8% annual coupon rate, semi-annual coupon payments, 10 years remaining maturity, and a current market price of ₹950. The calculator estimates an annual coupon income of ₹80, a semi-annual coupon of ₹40, and a YTM slightly above 8% — because the bond was purchased below face value, your effective return becomes higher than the coupon rate.

Now take a corporate bond with a $1,000 face value, a 5% coupon rate, annual coupon payments, a 5-year maturity, and a market price of $980. The calculator estimates an annual coupon income of $50, a maturity value of $1,000, and a YTM slightly above 5% — because the bond was purchased below par value, the total return increases from both coupon income and capital appreciation at maturity.

What Is a Bond?

A bond is a fixed-income instrument where an investor buys a loan issued by a government or non-government entity. The issuing entity becomes the borrower, promising to pay interest over a set period at regular intervals — at a fixed or variable rate known as the coupon rate — and to repay the entire principal by the time the bond matures. Bonds carry lower risk than stocks, with more stable income through periodic interest payments.

Key Bond Terms You Must Know

• Face/Par Value: The bond's worth at maturity — the total amount the issuer pays back.
• Coupon Rate: The rate at which the borrower pays the investor, annually or semi-annually.
• Coupon Frequency: The number of times interest payments are made in a year — annually, semi-annually or quarterly.
• Maturity Date: The date on which the issuer repays the bond's principal to investors.
• Time to Maturity: The period left before the bond reaches its maturity date.
• Bond Price: The current market value at which the bond is bought or sold — above or below face value.
• Yield: The effective return an investor earns based on the bond's current market price and coupon payments.
• Issuer: The entity borrowing money through the bond — a government, corporation, or financial institution.
• Credit Rating: An assessment of the issuer's repayment ability and default risk, from agencies like Moody's, S&P, or CRISIL.
• Call Option: Lets the issuer repay the bond early, usually when interest rates decline.
• Put Option: Lets investors sell the bond back to the issuer early, under specified conditions.

How Bond Pricing Works

Bond pricing works by calculating the present value (PV) of all future coupon payments and the face value repaid at maturity, discounted using the required market yield or YTM.

Price = Σ [Coupon ÷ (1 + r)^t] + FaceValue ÷ (1 + r)^n

Here, Coupon = periodic interest payment, r = required yield per period, t = coupon payment period, n = total number of periods.

Suppose you purchase a bond with face value $1,000 at 5% semi-annually for 10 years, with a required yield of 6%.

Step 1: Semi-annual coupon = 1,000 × 5% ÷ 2 = $25

Step 2: Yield per period = 6% ÷ 2 = 3%

Step 3: Total periods = 10 × 2 = 20

Step 4: Price = 25 × [1 − (1.03)^−20] ÷ 0.03 + 1,000 × (1.03)^−20 ≈ $925.61

The bond price here is below face value because although the coupon rate is 5%, the market requires a 6% return — since the bond pays lower interest than current market expectations, investors buy it at a discount.

Bond Yields Explained

Bond yield measures help you understand the return generated from a bond investment under different assumptions. Bond prices and bond yields move inversely — when bond prices fall, yields rise, and when bond prices rise, yields fall.

Current Yield

Current Yield measures the annual coupon income relative to the bond's current market price.

Current Yield = Annual Coupon ÷ Market Price × 100

Suppose you purchase a bond with a $1,000 face value at a 5% coupon rate, and a current market price of $950. Annual coupon = $50. Current Yield = 50 ÷ 950 × 100 ≈ 5.26%.

Current yield does not consider capital gain or loss at maturity, reinvestment of coupons, or time remaining to maturity — so it gives only a partial picture of total bond return.

Yield to Maturity (YTM)

Yield to Maturity (YTM) is the total expected annual return earned if the bond is held until maturity and all coupon payments are reinvested at the same yield. YTM is effectively the bond's Internal Rate of Return (IRR) — the discount rate that equates the bond price to the present value of all future cash flows, so it includes coupon income, capital gain/loss, maturity value, and the time value of money.

Suppose you buy a $1,000 bond paying a 5% annual coupon, currently trading at $925, with 10 years remaining. Although the coupon rate is only 5%, since the bond was purchased below face value, the capital appreciation at maturity increases the effective return above 5%. YTM assumes all coupon payments are reinvested at the same yield, which may not hold in reality — so relying on YTM alone carries reinvestment risk, especially when interest rates drop.

Yield to Call (YTC)

Yield to Call assumes the issuer redeems the bond early on the first callable date. The calculation is similar to YTM, but the maturity date is replaced by the call date, and the call price replaces the face value. For example, if a bond matures in 15 years but can be called after 5 years, YTC calculates the investor's return if the issuer repays the bond early.

Yield to Worst (YTW)

Yield to Worst is the lowest possible yield among YTM, YTC, and other call scenarios. Investors use YTW for conservative bond analysis, especially when interest rates decline and issuers may refinance expensive bonds early.

After-Tax Yield and Taxable-Equivalent Yield

After-tax yield shows the actual return remaining after paying taxes.

After-Tax Yield = Bond Yield × (1 − Tax Rate)

For example, if the bond yield is 8% and the tax rate is 30%: After-Tax Yield = 8% × (1 − 0.30) = 5.6%.

Taxable-equivalent yield helps compare tax-free bonds with taxable bonds.

Taxable-Equivalent Yield = Tax-Free Yield ÷ (1 − Tax Rate)

For example, if the municipal bond yield is 5% and the tax rate is 30%: Taxable-Equivalent Yield = 5% ÷ (1 − 0.30) ≈ 7.14% — meaning a taxable bond must offer 7.14% to match the tax-free return.

Clean Price vs Dirty Price (and Accrued Interest)

Clean price vs dirty price depicts the difference between a bond's quoted price and the actual amount an investor pays while purchasing it between coupon payment dates.

Clean Price is the quoted market price of the bond, excluding accrued interest — also called the ex-interest price.

Accrued Interest is the portion of coupon interest already earned by the seller before the bond is sold.

Accrued Interest = Coupon Per Period × (Days Since Last Coupon ÷ Days In Coupon Period)

Suppose a bond's face value is $1,000 with a 6% coupon rate, paid semi-annually — $30 every 6 months — and 90 days have passed in a 180-day coupon cycle.

Accrued Interest = 30 × (90 ÷ 180) = $15

Dirty Price is the actual amount the buyer pays, including accrued interest.

If the Clean Price is $980 and the Accrued Interest is $15: Dirty Price = 980 + 15 = $995.

Between coupon dates, the seller has already earned part of the upcoming coupon, so the buyer compensates the seller through accrued interest — ensuring a fair distribution of interest income between buyer and seller.

Day-Count Conventions Explained

Day-count conventions determine how interest and accrued interest are calculated between two bond dates. Even if two bonds have the same coupon rate, different day-count conventions can slightly change accrued interest, bond pricing, and yield calculations.

• 30/360: Every month is assumed to have 30 days, and every year has 360 days — common in corporate and municipal bonds.
• Actual/360: The actual number of calendar days is counted, but the year is assumed to have 360 days — common in money market instruments and commercial papers.
• Actual/365: Actual calendar days are counted, and the year is assumed to have 365 days — common for UK government securities, loans, and savings products.
• Actual/Actual: Both actual days passed and actual days in the year are used, with leap years using 366 days — common in government bonds and treasury securities, and considered the most accurate.

Suppose the bond face value is $1,000 at a 6% coupon rate, with 90 days already passed:

Different day-count conventions slightly affect accrued interest, dirty price, yield calculations, and bond settlement amounts — especially important in institutional bond trading and large-volume transactions.

Bond Duration & Interest-Rate Risk

Bond duration and convexity estimate how sensitive a bond's price is to changes in interest rates. Long-duration bonds are more sensitive to interest-rate movements than short-duration bonds, because they receive cash flows further into the future, making their present value more affected by changes in discount rates.

Macaulay Duration vs Modified Duration

Macaulay Duration measures the weighted average time required to receive all bond cash flows, including coupon payments and principal repayment, expressed in years.

Modified Duration tells you the approximate percentage change in bond price for a 1% change in yield.

Modified Duration = Macaulay Duration ÷ (1 + YTM)

Suppose a bond has a Macaulay duration of 5 years with a YTM of 4%: Modified Duration = 5 ÷ 1.04 ≈ 4.81. This means if interest rates rise by 1%, the bond price may fall by approximately 4.81%; if rates fall by 1%, the price may rise by approximately 4.81%.

Convexity and DV01

Convexity measures how bond duration changes when interest rates move significantly. Duration gives only a linear estimate, but the actual bond price-yield relationship is curved — bonds with higher convexity generally lose less value when rates rise, and gain more value when rates fall.

DV01 measures the dollar change in bond price for a 1 basis point (0.01%) change in yield. If a bond's price changes by $0.08 when yield changes by 1 basis point, its DV01 is $0.08 — meaning for every 0.01% change in interest rates, the price changes by approximately $0.08. DV01 is widely used by bond traders and fixed-income portfolio managers.

Why Bond Prices & Interest Rates Move Inversely

Bond prices and interest rates move inversely — when interest rates rise, bond prices fall, and when interest rates fall, bond prices rise. This happens because older bonds compete with newly issued bonds carrying different interest rates. The relationship is also convex, not perfectly straight — price gains during falling rates are usually larger than price losses from an equal rise in rates.

Suppose a bond worth ₹1,000 pays 5% annual interest (₹50/year). If market interest rates rise to 7%, new bonds pay ₹70/year on the same ₹1,000 — so nobody would buy the older 5% bond at full price, and its price has to fall below ₹1,000. Now imagine rates fall from 5% to 3% instead — the older bond paying ₹50 annually becomes more attractive than new bonds paying only ₹30, so investors are willing to pay more than ₹1,000 for it.

• Premium Bond: Trades above face value when the coupon rate is greater than the market interest rate.
• Discount Bond: Trades below face value when the coupon rate is lower than the market interest rate.
• Par Bond: Trades at face value when the coupon and market interest rates are equal.

Types of Bonds (and How Pricing Differs)

• Government Bonds (G-Sec / Treasury): Lowest default risk, stable coupons, highly liquid — if the central bank lowers rates, existing high-coupon G-Secs become more valuable and prices rise sharply.
• Corporate Bonds: Higher coupon than government bonds; credit risk depends on company quality — AAA-rated bonds usually trade at higher prices than lower-rated ones.
• Municipal Bonds: Often tax-advantaged with lower risk — since some offer tax-free income, investors accept lower yields, which increases prices.
• Zero-Coupon Bonds: Issued at a deep discount with no periodic interest — investors profit purely from price appreciation toward face value.
• High-Yield (Junk) Bonds: Issued by financially weaker companies at very high coupon rates, to compensate for higher default risk.
• Floating-Rate Bonds: Coupons linked to a benchmark rate, adjusting periodically — lower interest-rate risk and smaller price fluctuations.
• Inflation-Linked Bonds: Principal or coupon adjusts with inflation, protecting purchasing power — becomes more attractive as inflation rises.
• Callable Bonds: Let the issuer repay early, usually when rates fall — investors demand higher yields to compensate for call risk.
• Puttable Bonds: Let investors sell back to the issuer early — this added protection means they trade at higher prices.
• Perpetual Bonds: No maturity date, paying interest indefinitely — very high duration risk since the principal is never repaid.

Common Mistakes When Using a Bond Calculator

• Using Clean Price Instead of Dirty Price: Calculating YTM using only clean price without accrued interest produces inaccurate yield results.
• Mismatching Coupon Frequency and Yield Basis: Using an annual yield with semi-annual coupon inputs without adjustment leads to incorrect pricing and yield estimates.
• Percentage vs Decimal Errors: Entering 6 instead of 0.06 in formulas generates unrealistic bond values and yields.
• Confusing Current Yield with YTM: Current yield measures coupon income only, while YTM includes coupon payments, maturity value, and capital gain/loss.
• Ignoring Day-Count Conventions: Different conventions such as 30/360 or Actual/365 change accrued interest and settlement calculations.
• Rounding Too Early: Early rounding during intermediate steps distorts bond price, duration, and yield calculations.

Avoiding these mistakes improves portfolio planning, risk management, income forecasting, and your overall understanding of how bonds react to changing market conditions.

Bond Calculator vs YTM / Duration / SIP Calculators

Bond calculator vs YTM/duration/SIP calculator depicts how different fixed-income calculators focus on different aspects of bond investing — pricing, return estimation, interest-rate sensitivity, and recurring investment planning.

Bond Calculator: A broad tool for bond pricing, coupon calculation, accrued interest, and maturity value estimation, combining multiple bond calculations in one place.

YTM Calculator: Specifically calculates Yield to Maturity — the total annual return earned if the bond is held until maturity — focusing narrowly on return estimation rather than the full pricing picture.

Duration Calculator: Tells you how sensitive a bond price is to interest-rate changes, calculating Macaulay duration, modified duration, DV01, and interest-rate risk — focused on risk measurement.

Bond SIP Calculator: Estimates the future value of recurring investments into debt instruments, focusing on long-term wealth accumulation through periodic investing rather than pricing a single bond.

While a bond calculator provides an overall valuation framework, the other calculators are more specialised for specific calculations.