Bond Duration vs Maturity: How to Understand Interest-Rate Risk

Maturity tells you when a bond's principal is scheduled to be repaid; duration helps describe the timing of cash flows or sensitivity of price to yields, depending on the measure. They are related but not interchangeable. A bond with ten years left need not have ten-year modified duration, and low duration does not eliminate credit or liquidity risk.

Separate the three common duration ideas

Macaulay duration is the present-value-weighted average time to receive contractual cash flows under the calculation's assumptions. Modified duration adjusts that measure to estimate price sensitivity to a yield change. Effective duration is commonly used where cash flows can change with rates, such as callable instruments.

FINRA's duration explanation distinguishes these concepts and warns that duration is not simply time to maturity. Check which measure a factsheet reports before comparing products. A column labelled only “duration” may need further clarification.

For a conventional zero-coupon bond, Macaulay duration equals remaining maturity because all cash arrives at the end. Modified duration is different because it includes the yield adjustment. Avoid repeating the shorthand that every kind of duration equals maturity for a zero-coupon bond.

Calculate a simple example

Take a hypothetical two-year bond paying ₹100 after one year and ₹1,100 after two years, with an annual yield of 10%. Present values are ₹90.91 and ₹909.09, so price is ₹1,000.

Macaulay duration is (1*90.91+2*909.09)/1000, approximately 1.909 years. Modified duration for this annual-payment illustration is 1.909/1.10, approximately 1.736. Maturity is two years. The early coupon brings the weighted cash-flow time below the final repayment date.

For a small yield increase, approximate percentage price change as -Modified duration*Change in yield, using the yield change as a decimal. A 0.50-percentage-point increase is 0.005, so the estimate is -1.736*0.005, or about minus 0.868%.

This is a local approximation, not an exact revaluation. Reprice every cash flow for a more accurate answer. The example assumes unchanged promised cash flows, a single annual yield and no accrued-interest complications, default or transaction costs.

Interpret higher and lower duration

If one hypothetical fund has modified duration two and another six, a parallel one-percentage-point yield increase implies approximate price effects of minus 2% and minus 6%, respectively, before other influences. The same logic reverses for a small decline, subject to convexity and cash-flow features.

Longer maturity usually increases duration when other relevant features are comparable. Higher coupons usually reduce it because more value arrives earlier. Yield level also affects duration. Comparing maturity alone ignores these differences and can misstate rate exposure.

A floating-rate bond can have long final maturity but relatively short rate duration because coupons reset. That does not remove issuer credit risk, spread risk, reset lags or liquidity issues. Read the reference-rate and spread terms rather than treating floating as a synonym for stable value.

Apply the measure to an actual holding

Check the calculation date, measure, portfolio composition and yield assumptions. Bond-fund duration changes as holdings age, yields move or managers trade. A factsheet is a dated snapshot, not a permanent promise about future sensitivity.

Duration also assumes a simplified yield movement. Actual yield curves can twist, with short rates rising while long rates fall. Credit spreads can move independently of government yields. A portfolio with multiple exposures may need key-rate or scenario analysis rather than one duration number.

Convexity captures curvature in the price–yield relationship; larger changes can depart materially from the straight-line estimate. Embedded options can alter the relationship further. The MSRB's interest-rate-risk guide notes that duration does not provide a complete picture of bond rate risk.

Use duration to estimate a plausible mark-to-market move and compare it with when you need the money. Then assess default, inflation, liquidity and costs separately. No rate forecast or fund recommendation is made here. A suitable holding period cannot be established from one sensitivity number without considering the investor's cash needs and the full instrument terms.

Quick questions, clear answers

Does duration tell me the expected return?

No. It mainly summarises cash-flow timing or rate sensitivity under a defined method. Expected or realised return also depends on yield, credit outcomes, reinvestment, fees and sale timing. A higher-duration fund is not automatically a higher-return investment.

Can a low-duration fund lose money?

Yes. Yields or credit spreads can rise, issuers can default, and liquidity problems can affect prices. Low duration limits only one dimension of exposure under the measure's assumptions. Examine holdings and credit quality rather than relying on the category label alone.

Should I match duration exactly to my goal date?

Matching assets to liabilities can be useful, but duration matching requires assumptions about cash flows, rebalancing and yield changes. It is more than choosing a fund with a similar number. For a personal goal, access, principal uncertainty and product structure also need consideration.

About this guide

Aniket Thakur prepared this educational guide from secondary research checked on 22 October 2026. All numerical illustrations are hypothetical unless stated otherwise. No investment product was tested, and no individual financial circumstances were assessed. Read the cited primary material and relevant product documents before acting.