Duration is a fixed-income concept that measures the weighted average timing of a bond’s expected cash flows and, from that timing structure, its first-order sensitivity to changes in yield. In practical terms, duration helps explain why two bonds with the same maturity can still react differently when yields move.
That distinction matters because duration is not the same thing as calendar maturity. Maturity tells you when principal is due. Duration reflects how the full stream of coupons and principal is distributed across time, and how much each payment contributes to present value. A bond can therefore mature in ten years while having a duration meaningfully below ten years if a larger share of its value is returned earlier through coupons.
How duration is formed
Duration begins with a bond’s cash-flow structure. Each coupon payment and the final principal repayment contribute to the bond’s total value, but they arrive at different dates. Duration measures where the economic center of those payments sits once the cash flows are discounted back to the present.
Coupon size changes that center. Higher coupons return more value earlier, which pulls duration inward. Lower coupons leave more value concentrated in the final payment, which pushes duration outward. A zero-coupon bond makes the logic especially clear because all value arrives at maturity, so duration and maturity coincide.
Yield level matters as well. Duration is calculated from present values, not only from contractual payment dates. When yields change, the relative weight of earlier and later cash flows changes too. That is why duration is best understood as a property of the bond as currently priced rather than as a fixed label attached to the instrument forever.
What duration measures
Bond prices are the present value of future cash flows. When yields rise, those cash flows are discounted more heavily. When yields fall, they are discounted less heavily. Duration is the compact measure that summarizes how sensitive a bond’s price is to that change in discounting.
Shorter-duration bonds usually show smaller price changes because more of their value is recovered sooner. Longer-duration bonds usually show larger price changes because more of their value depends on cash flows that arrive further into the future. Duration therefore describes the scale of interest-rate sensitivity embedded in the bond’s structure.
Duration versus maturity
Maturity is a legal endpoint. Duration is a weighted timing measure. The two are related, but they are not interchangeable. A long-maturity bond often has high duration, but coupon size, yield level, and remaining cash-flow structure can materially change the comparison.
That is why the shortcut “longer maturity means higher sensitivity” is only a rough rule. Two bonds can share the same maturity and still have different durations if one pays larger coupons or is priced at a different yield. Duration gives the more useful answer when the question is about price responsiveness rather than contract length.
Duration versus duration risk
Duration risk is closely related to duration, but it is not the same concept. Duration is the measure itself: the weighted timing of cash flows and the resulting price sensitivity to yield changes. Duration risk is the exposure that follows from holding an asset with that sensitivity.
Put differently, duration belongs to bond mechanics and valuation structure. Duration risk belongs to the consequences of that structure when yields move. This page focuses on the definition and mechanics of duration itself, while duration risk is the separate question of how that sensitivity can affect realized price behavior.
Duration and the discount-rate logic of valuation
Duration is closely tied to discount rate mechanics, but it is not itself a discount rate. The discount rate is the valuation input used to convert future cash flows into present value. Duration measures how responsive bond prices are when that input changes.
This boundary keeps the concept clear. One is the rate used in valuation; the other is the sensitivity that emerges from changes in that rate. Duration does not tell you where yields should go or what policy makers will do next. It isolates the cash-flow timing and valuation mechanics inside the bond.
Where duration fits in equities and bonds analysis
Within Equities and Bonds, duration belongs first to the internal language of fixed income. It explains why bonds with different cash-flow profiles respond differently across changing yield environments. That bond-side understanding comes before broader cross-asset interpretation.
From there, the same discounting logic can help explain why long-dated cash-flow assets are often more sensitive when yields reprice, which is part of the wider background behind why higher yields hurt stocks. But duration itself remains a bond valuation concept, not a full theory of equity performance.
What duration does not capture
Duration does not mean expected return, and it does not describe every risk a bond carries. Credit risk, liquidity conditions, and issuer-specific stress can all affect bond prices for reasons separate from pure interest-rate sensitivity.
It is also not a perfect rule for every possible market move. Duration is most useful as a first-order approximation of price sensitivity around a given yield level. For larger rate moves or more complex bond structures, realized price behavior can deviate from what duration alone would suggest.
FAQ
Why can two bonds with the same maturity have different durations?
Because maturity tells you only when principal is repaid. Duration depends on the full pattern of coupons and principal, plus the present-value weight of each payment. A higher-coupon bond usually has a shorter duration than a lower-coupon bond with the same maturity because more value comes back earlier.
Is duration higher when coupon payments are lower?
Usually yes. Lower coupons leave more of the bond’s value concentrated in the final payment, which extends the weighted average timing of cash flows and increases price sensitivity to yield changes.
How is duration different from duration risk?
Duration is the measure of timing and sensitivity. Duration risk is the exposure created by that sensitivity when yields change. The first describes bond mechanics; the second describes the vulnerability that follows from those mechanics.
Why is duration not the same as a discount rate?
The discount rate is the input used to value future cash flows. Duration is the measure of how much price tends to respond when that input changes. They are connected, but they answer different questions.