Duration vs maturity (bond ETFs): the simple difference

If you remember one thing: maturity tells you when you get repaid; duration tells you how much the price can move when interest rates change.

Short version

• Maturity (or “term”) is the time until a bond repays principal.
• Duration is an interest-rate sensitivity measure (a practical risk number for bond ETF price changes).
• In bond ETFs, the “average maturity” you see is often not the best single number to estimate rate risk — duration is.

Why beginners mix them up

In everyday language, “long-term bonds” sounds like “big interest-rate risk”. That’s often true — but not always. A bond’s cash flows (coupons) arrive before the final maturity date, and that changes how sensitive the bond is to rate changes.

What is maturity?

A bond’s maturity is the date when the principal is repaid. For an ETF, you’ll typically see something like: weighted average maturity (WAM) or an average maturity range (short / intermediate / long).

Maturity helps you understand the “style” of the bond exposure (short vs long), but it does not directly tell you the size of price moves.

What is duration (in plain English)?

Duration is a way to summarize how much a bond or bond ETF price tends to move when yields change. The most practical approximation you’ll see is:

If yields move by 1%, a fund with duration ~5 may move by about 5% in the opposite direction (all else equal).

Note: this is an approximation. Big rate moves, changing credit spreads, and convexity make real outcomes differ. But as a beginner tool, it’s very useful.

A simple example (why maturity ≠ duration)

• Zero-coupon bond: no coupons, only one payment at the end. Its duration is roughly its maturity.
• Coupon bond: you receive coupons along the way. Those earlier cash flows reduce duration versus maturity.

That’s why two bond ETFs with similar average maturity can still behave differently if their coupons, yields, or holdings differ.

For bond ETFs, what number should you actually check?

When your question is “how painful will this be if rates rise?” the best first-number is usually: effective duration (sometimes “modified duration”).

• Higher duration → bigger price swings for the same rate move.
• Lower duration → smaller swings, but usually lower yield (not always).

How to choose duration (a calm decision framework)

1) Match bonds to your time horizon

If you might need the money in a few years, avoid taking big duration risk just to chase yield. Short-term bond ETFs can be boring — and that’s the point.

2) Decide what bonds do in your portfolio

• “Stability / ballast” role: typically shorter duration (less rate volatility).
• “Diversifier vs equities” role: sometimes intermediate duration (more sensitivity, potentially better recession hedge).
• “Rate bet” role: long duration is basically a view on rates. Treat it as such.

3) Don’t ignore credit risk

Duration is about interest-rate risk. But bond ETFs also move because of credit spreads (especially high-yield). In a stress period, credit spreads can dominate.

Where to find duration for an ETF

Look in the fund’s factsheet / KID / provider page for “effective duration” or “modified duration”. If you only see maturity, search the factsheet PDF — duration is usually there.

Key takeaways

• Maturity = “when the bonds repay”.
• Duration = “how sensitive the price is to rates”.
• For most bond ETF decisions, duration is the more actionable risk number.

Educational only, not investment advice.