Yield to maturity (YTM) is a bond's internal rate of return (IRR). Discounted at that one rate, the payments still to come add up to the price you pay.
Your whole investment grows at that rate only under three conditions. You hold to maturity, the issuer pays on time, and every coupon earns the same rate once you get it.
YTM is the bond's internal rate of return
Mathematically, FINRA explains, it's the discount rate at which a bond's future coupons and principal sum to its price. That's also how an internal rate of return is defined for any stream of payments.
C is one coupon, F the face value and n the coupons left. With no closed-form solution, the calculator narrows a range of rates until both sides match.
Take a 6-year bond paying a 5% coupon once a year, bought at $950. As cash flows, that's −$950 today, $50 in years 1 to 5, and $1,050 in year 6:
Paste that list into the IRR calculator, and it returns the same rate as this calculator with annual coupons. The table adds a second bond with the same $350 profit, paid all at the end:
| Bond bought at $950 | Coupon rate | Face value repaid in year 6 | Yield to maturity (IRR) |
|---|---|---|---|
| Pays $50 every year | 5% | $1,000 | 6.02% |
| Pays nothing until year 6 | 0% | $1,300 | 5.37% |
Both turn $950 into $1,300. Yet the first yields 6.02% and the second 5.37%, because the first pays you sooner.
The yield assumes every coupon earns it too
The second bond is really the first one with its coupons left in a drawer until year 6. Same cash, lower yield: idle coupons earn nothing.
FINRA says YTM doesn't require you to reinvest, though its computations generally assume you do. It also points out that rates regularly fluctuate, which makes reinvesting each coupon at the same rate virtually impossible.
The longer the bond, the more this matters. Here are four 6% bonds bought at their $1,000 face value, with semi-annual coupons left idle:
| 6% bond, years to maturity | Face value plus idle coupons at maturity | Growth rate of your $1,000 |
|---|---|---|
| 2 yr | $1,120 | 5.75% |
| 5 yr | $1,300 | 5.32% |
| 10 yr | $1,600 | 4.76% |
| 30 yr | $2,800 | 3.46% |
Each yields 6% to maturity, since each cost its face value. But over 30 years, idle coupons leave your $1,000 growing at just 3.46% a year. You can run this check yourself: enter the total as the face value, a 0% coupon and your price.
On a 30-year bond, most of the return is interest on interest
What would it take to earn the full 6% on that 30-year bond? Your $1,000 would have to compound at 3% every six months, 60 times:
The face value and the 60 coupons of $30 bring in $2,800. The other $3,091.60 has to come from reinvested coupons earning 6% for decades. That's more than all the coupons put together.
So a long bond's promise leans on rates you'll only get years from now. If they fall, your overall return lands below the YTM.
How a YTM lines up against a CD's APY
A CD's annual percentage yield (APY) rests on a similar assumption. Under Regulation DD, banks compute it as if all principal and interest remain on deposit for the entire term. On a compounding CD, the bank reinvests for you. A bond pays its coupons out, and reinvesting them is up to you.
The two are also stated differently. The calculator gives the rate per coupon period times the coupons a year, while an APY includes compounding:
| YTM with coupons twice a year | The same yield stated as an APY |
|---|---|
| 3.00% | 3.02% |
| 4.00% | 4.04% |
| 5.00% | 5.06% |
| 6.00% | 6.09% |
A bond with a 5% YTM matches a CD with a 5.06% APY. That holds only if each coupon is reinvested at 5%. The APY calculator converts other compounding frequencies.
Cashing out early differs too. Regulation DD lists early withdrawal penalties among the terms a CD must disclose. A bond sells at the market price instead. FINRA notes that price may be more or less than holding to maturity would pay.
Coupons and price gains aren't taxed alike
FINRA adds that YTM doesn't consider taxes or brokerage costs. Here's what IRS Publication 550, for 2025 returns, says about two common cases:
- Accrued interest you pay. Buy between coupon dates and part of your price is interest the seller earned. When the next coupon arrives, treat that part as a return of capital, not interest income. It lowers your basis in the bond instead.
- A discount on a tax-free bond. Interest on state and local bonds generally isn't taxable. But market discount on a tax-exempt bond is not tax exempt. If you bought after April 30, 1993, you can choose to include it as taxable interest as it builds up. Otherwise, any gain from market discount is taxable when you dispose of the bond.
So a municipal bond bought below face value is only partly tax-free, unless the whole discount dates from its issue. Publication 550 treats that original issue discount (OID) as tax-exempt interest. For a market-discount bond, entering the full YTM in the tax-equivalent yield calculator gives too high a result.
Getting the inputs right
- Price. Use the dollar price per bond, before accrued interest. The calculator counts whole coupon periods, as if you bought on a coupon date.
- Years to maturity. Count to the maturity date. Fractions round to whole coupon periods, so 6.8 years with semi-annual coupons counts as 7.
- Callable bonds. If the issuer can repay early, run the yield to call calculator too. FINRA says callable-bond investors should always compare the two; the lower one is the yield to worst.
Sources
- FINRA, Understanding Bond Yield and Return (August 11, 2022)
- FINRA, Bonds (accessed September 27, 2026)
- CFPB, Regulation DD, Appendix A to Part 1030: Annual Percentage Yield Calculation
- eCFR, 12 CFR 1030.4, Regulation DD account disclosures (as of September 24, 2026)
- IRS, Publication 550, Investment Income and Expenses (for 2025 returns)