Bond YTM Calculator
Calculate bond yield to maturity for fixed income investment analysis.
What this calculator does
This calculator computes a bond's yield to maturity — the annualized return you earn buying at today's price and holding until the bond matures. It combines the coupon income you receive along the way with the gain or loss between the purchase price and the face value repaid at the end.
YTM exists because the coupon rate alone tells you almost nothing about return once a bond trades away from par. A 4 percent coupon bond bought at 92 and a 6 percent coupon bond bought at 108 may deliver near-identical returns. Yield to maturity is the common measure that makes them comparable.
When to use it
Use it when comparing individual bonds for purchase, when deciding whether a bond you already hold is worth keeping versus selling at the current market price, or when checking that a broker's quoted yield matches what the price and terms actually imply.
It is also the tool for reading the market. Comparing the YTM on a corporate bond against a Treasury of the same maturity gives you the credit spread — the extra yield demanded for taking on that issuer's default risk. A widening spread across a sector is often the earliest sign of trouble. For bond funds rather than individual bonds, use the fund's SEC yield instead, since a fund has no maturity date.
Understanding the inputs
Face value is the amount repaid at maturity, conventionally $1,000 for US corporate bonds. Purchase price is what you pay today, quoted in the market as a percentage of par — a quote of 92 means $920.
The coupon is the annual interest payment in dollars, so a 4 percent coupon on $1,000 face is $40. This calculator assumes annual coupon payments; most US corporate and Treasury bonds actually pay semiannually, which raises the effective yield slightly. Years to maturity is the remaining time, not the original term. Note that quoted prices are usually clean prices, excluding accrued interest you also pay the seller.
How is this calculated?
Yield to maturity is the discount rate at which the present value of all remaining coupons plus the redemption of face value equals the current market price. There is no closed-form solution, so it is solved numerically. Current yield, by contrast, is simply the annual coupon divided by the market price and ignores any gain or loss at redemption.
A worked example
Consider a bond with $1,000 face value, a 4 percent coupon paying $40 a year, six years to maturity, trading at $920. Current yield is $40 divided by $920, or 4.35 percent — but that ignores the $80 you gain when the bond repays at par.
The approximation formula adds the annualized gain of $13.33 to the $40 coupon and divides by the average of price and par, giving about 5.56 percent. Solving iteratively gives a true YTM of roughly 5.61 percent. So the bond returns well over its 4 percent coupon rate, and the difference between the discount and the coupon rate is doing more than a quarter of the work.
Limitations and assumptions
The largest assumption is reinvestment: YTM assumes every coupon is reinvested at the same yield until maturity. In a falling rate environment that will not happen, and your realized return will fall short of the quoted figure. It also assumes you actually hold to maturity — sell early and your return depends entirely on the price you get.
The model treats coupons as annual and default as impossible, neither of which is generally true. It cannot handle call or put features, floating rate notes, sinking funds, or inflation-linked bonds like TIPS. It also excludes tax, accrued interest, and dealer markups on small retail bond purchases, which can be substantial. This is not investment advice.
Common Questions
- What does yield to maturity actually measure?
- The total annualized return if you buy a bond at today's price and hold it to maturity, collecting every coupon and the face value at the end. It folds three things into one number: coupon income, the gain or loss between price and par, and the time remaining. It is effectively the bond's internal rate of return.
- How is YTM different from the coupon rate?
- The coupon rate is fixed at issue and never changes — it is a percentage of face value. YTM moves constantly with the market price. A bond with a 4 percent coupon bought at 92 cents on the dollar yields well above 4 percent, because you also collect the 8 cent gain when it matures at par.
- What is current yield and why does it differ?
- Current yield is just the annual coupon divided by the price, so it captures income but ignores the pull to par. For a $1,000 bond with a $40 coupon trading at $920, current yield is 4.35 percent while YTM is about 5.6 percent. Current yield always sits between the coupon rate and YTM for a discount bond.
- Why does the bond price fall when interest rates rise?
- Because your fixed coupon becomes less attractive against newly issued bonds paying more. The price has to fall until the yield matches what the market now demands. Longer-dated bonds fall harder — a 10-year bond loses roughly twice as much value as a 5-year for the same rate move.
- Is the approximation formula good enough?
- For a quick check, usually. On a $1,000 bond at $920 with a 4 percent coupon and six years left, the approximation gives 5.56 percent against a true YTM of 5.61 percent. The gap widens for bonds trading far from par or with long maturities, where iterative solving is worth the extra effort.
- What assumption does YTM make that might not hold?
- That every coupon is reinvested at the YTM itself. If rates fall and you reinvest coupons at 3 percent instead of 5.6, your realized return is lower than the quoted YTM. This reinvestment assumption is the main reason zero-coupon bonds, which have no coupons to reinvest, deliver exactly their stated yield.
- What about callable bonds?
- For those, yield to call matters more. If a bond trades above par and the issuer can redeem it early, they usually will when rates fall, cutting your income short. Convention is to quote yield to worst — the lower of yield to maturity and yield to each call date. This calculator assumes no call feature.
- How are bond returns taxed?
- Coupon interest from corporate bonds is ordinary income at your marginal federal rate plus state tax. Treasury interest is federally taxable but state-exempt. Municipal interest is generally federally exempt. A discount bond bought below par may also generate market discount taxed as ordinary income at maturity rather than as a capital gain.
- Does YTM tell me whether a bond is a good buy?
- Only relative to bonds of similar credit quality and maturity. A yield noticeably above comparable issues is usually compensation for default risk, not a bargain. Compare a corporate YTM against the Treasury yield for the same maturity — that spread is the market's price for the issuer's credit risk.