How the Yield to Maturity Calculator works
Yield to maturity (YTM) is the single annualized discount rate that ties a bond's current market price to every cash flow it will pay between now and maturity: each coupon plus the face value returned at the end. It is the standard way to compare bonds that have different prices, coupon rates, and maturities on one common scale.
The bond pricing equation
A bond's price is the present value of its remaining cash flows discounted at the periodic yield. For face value F, a coupon payment per period C (annual coupon rate × F, divided by payments per year m), N total remaining payments (years to maturity × m), and periodic yield y/m:
Price = Σt=1N C / (1 + y/m)t + F / (1 + y/m)N
There is no algebraic rearrangement that isolates y on one side of this equation, so the calculator searches for it numerically: it repeatedly narrows a range of candidate annual yields with a bisection search, computing the price each guess would produce and comparing it to the price you entered, until the two match to a very small tolerance.
Worked example
Take a $1,000 face-value bond with a 5% annual coupon paid semiannually, 10 years to maturity, currently priced at $950. Each period pays $25 (half the $50 annual coupon) over 20 periods. Because the bond trades below its $1,000 face value, its YTM comes out above the 5% coupon rate — roughly 5.66% annualized — since the buyer collects both the coupons and the $50 gain as the price converges to par at maturity. The current yield, by contrast, is just $50 / $950 ≈ 5.26%, since it ignores that price convergence entirely.
What moves YTM most
- Price relative to face value: the single biggest driver. A discount bond (price below face) always has YTM above its coupon rate; a premium bond (price above face) always has YTM below its coupon rate.
- Coupon rate: a higher coupon delivers more cash sooner, which raises YTM for a given price and maturity, all else equal.
- Years to maturity: for a discount or premium bond, a shorter remaining term concentrates the pull-to-par effect into fewer years, which moves YTM further from the coupon rate than the same price gap would over a longer term.
- Payment frequency: more frequent compounding of the same nominal annual coupon changes the periodic discounting slightly, so the frequency you select must match how the bond actually pays.
What YTM assumes
YTM assumes the bond is held to maturity, every coupon is reinvested at that same YTM rate, and every payment arrives on schedule with no default. It does not account for callable features, credit risk, taxes, or transaction costs, so a bond's realized return can differ from its quoted YTM if any of those assumptions do not hold.