What Is a Bond's Yield to Maturity?
Two bonds can carry the same stated interest rate and still offer very different actual returns, depending on what price you pay for them. Yield to maturity is the number that accounts for that gap.
The short answer
Yield to maturity is one of the core figures used to evaluate bonds: it’s the total return an investor can expect to earn on a bond if it’s held until it matures, expressed as an annual percentage. It accounts for the bond’s current price, its face value, its coupon (interest) payments, and the time remaining until maturity — not just the stated coupon rate printed on the bond. Because bond prices move in the secondary market, yield to maturity often differs from the coupon rate.
Why the coupon rate alone isn’t enough
A bond’s coupon rate is fixed at issuance and tells you the interest payment as a percentage of the bond’s face value. But bonds are frequently bought and sold at prices above or below that face value on the secondary market, and the price paid changes the actual return an investor receives. If a bond is purchased below its face value, the buyer benefits both from the coupon payments and from the gain when the bond returns to full face value at maturity, which pushes the effective yield above the coupon rate. If purchased above face value, the effective yield ends up below the coupon rate.
A simplified illustration
Imagine a hypothetical bond with a face value of $1,000 and a coupon rate of 4%, paying $40 a year. If an investor buys that bond at exactly $1,000, the yield to maturity is close to 4%, matching the coupon. But if that same bond can be bought at a discount, say $950, the investor still collects the same $40 annual payments and receives the full $1,000 at maturity — a combination that produces a yield to maturity noticeably higher than 4%, because of the added gain from buying below face value. The reverse happens if the bond is purchased at a premium above $1,000.
How it connects to duration and price movement
Yield to maturity and a bond’s duration work together to describe a bond’s overall behavior: yield to maturity estimates the return if held to the end, while duration estimates how much the bond’s price might swing along the way if interest rates change. A bond with an attractive yield to maturity can still experience real price volatility before maturity, so the two measures are complementary rather than substitutes for one another.
Comparing bonds fairly
Yield to maturity is especially useful for comparing bonds that have different coupon rates, prices, or maturity dates, since it distills all of those variables into one comparable annual figure — useful when weighing how a bond holding fits into a broader, diversified portfolio. This is part of why yield to maturity is generally viewed as a more complete measure than the coupon rate alone when evaluating an individual bond or a bond fund, particularly for an investor trying to weigh several options against each other.
The takeaway
Yield to maturity gives a fuller picture of a bond’s likely return than the coupon rate by itself, because it folds in the price actually paid and the time remaining until the bond matures. It’s not a guarantee of what an investor will receive, since it assumes the bond is held to maturity and that all payments are made on schedule, but it remains one of the more useful single numbers for comparing bonds against each other.