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How do interest rates affect a currency’s exchange rate?

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GlobalPublished 6 October 2026 · Written by BuyMeWhiskey Editorial Team · How we check facts

Higher interest rates can support a currency by increasing the expected return on assets denominated in it, all else equal. In practice, inflation, risk, growth and expectations can dominate, so a rate rise does not guarantee a stronger currency.

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Read Bank of England material on monetary policy and exchange rates for the basic interest-rate channel.

Read Bank of England monetary-policy guidance

Run your own numbers: Compound interest and savings calculator.

The basic channel

When rates rise, local-currency bonds and deposits can become more attractive relative to alternatives. Investors may need to buy the currency to invest, creating upward pressure.

That is a relative comparison: what matters is the expected return versus another country, not one rate in isolation.

Markets price expectations

If a rate rise was already expected, the currency may move before the announcement. A surprise change can have a larger immediate effect.

Markets also consider where rates are likely to go next, not just today’s rate.

Money supply and rates

In a simplified model, more liquidity can put downward pressure on short-term interest rates, while tighter monetary conditions can push them higher. Modern central-bank operations are more complicated than the textbook model.

Lower relative rates can reduce the attraction of that currency’s assets, but inflation and growth still matter.

Risk can override the rate effect

A high rate can coexist with a falling currency when investors perceive high economic, political or financial risk. Safe-haven flows can move in the opposite direction.

Negative risk-free rates

A negative risk-free rate means the benchmark low-risk return is below zero in the relevant market and period. It does not mean every investment has a negative return.

Foreign investors

A foreign investor cares about the asset return, expected currency movement, inflation and hedging costs together. A higher local yield can be unattractive if the currency is expected to weaken.

Useful rule

Higher relative rates can support a currency, especially when the move is unexpected and inflation expectations are contained. It is a tendency rather than a law.

Exchange rates are driven by relative returns

The familiar story is that a higher interest rate supports the currency because investors may prefer assets offering a higher return. That is useful as a first pass, but the comparison is always relative. If another country raises rates even more, the currency with the lower increase can still weaken. Investors also care about inflation, political risk, growth prospects and what they believe the central bank will do next.

Expectations matter because markets can react before the policy meeting. If traders have already priced a quarter-point increase, the announcement may cause little movement. A surprise decision can produce a larger move because it changes the expected path of returns. That is why a chart showing the policy rate and exchange rate alone cannot establish a simple one-for-one relationship.

Why money supply is not a mechanical switch

In a simplified economic model, an increase in the money supply can put downward pressure on interest rates when the demand for money is unchanged. In the real economy, however, central-bank policy, banks’ balance sheets, demand for credit and inflation expectations all interact. A larger supply of money therefore does not guarantee a specific interest rate or currency movement.

The same caution applies to a negative risk-free rate. A benchmark yield below zero does not mean every asset should have a negative expected return. Risk premia, cash-flow timing, currency effects and investor preferences still influence the price of a security. Exchange rates and interest rates are linked through these expectations rather than through a single fixed formula.

Markets price the path, not merely today’s rate

Currency traders respond to the expected future path of policy as well as the current policy rate. A central bank that has already signalled higher rates may see little exchange-rate benefit from an increase that investors expected months earlier. Conversely, a softer statement about future policy can weaken a currency even when the current rate has not changed. Relative inflation, economic prospects and perceived risk can also shift the attractiveness of one currency against another, which is why the interest-rate relationship is best understood as one influence inside a wider market-pricing process.

Worked example

Illustrative example: An investor considers moving £100,000 into a UK asset after an illustrative expected return increase of 2%.

Illustrative extra return: £100,000 × 0.02 = £2,000.

If the investor expects sterling to lose more than that advantage, the higher UK rate may not be enough to attract the capital. The £2,000 result is a sensitivity figure rather than an exchange-rate prediction.

The percentage change is a simple sensitivity example. Real exchange-rate moves depend on expectations, relative interest rates and other macroeconomic factors, so the calculation is deliberately not presented as a forecast.

The calculation isolates only the return differential. It does not convert that two-percentage-point change into a promised currency move. An investor comparing two countries would normally consider the expected rate path, inflation outlook and exchange-rate exposure together, because a currency loss can outweigh a modest difference in the quoted interest rate.

Why do higher rates attract foreign investors?#

Higher rates can increase expected returns on assets in that currency, but investors also consider inflation and currency risk. The effect is strongest when the rate difference is meaningful and not already priced in. The relevant rate comparison is between currencies, not a single country’s rate viewed in isolation.

Does raising rates always strengthen a currency?#

A higher interest rate does not guarantee that its currency will rise. Expectations, weak growth, inflation or higher rates elsewhere can outweigh the effect. Exchange rates are relative prices between two currencies. An expected central-bank move can be reflected in exchange rates before the decision itself.

Why can more money supply lower rates?#

In a simplified liquidity model, more money can reduce the price of short-term funds and push rates lower. Modern monetary systems have additional mechanisms. Inflation expectations can offset some of the attraction created by a higher nominal interest rate. The direction therefore depends on the model and the policy response, not on money supply alone. The direction therefore depends on the model and the policy response, not on money supply alone.

Can more money supply weaken a currency?#

It can contribute through lower rates and higher inflation expectations, but the result is not automatic. Output, policy expectations and global capital flows also matter. A currency can weaken after a rate increase when investors expected an even larger increase or a stronger outlook elsewhere.

What is a negative risk-free rate?#

It means the benchmark low-risk return is below zero for the relevant instrument. It does not mean all investments lose money. Money-supply relationships are model-dependent and do not produce a fixed exchange-rate outcome. The relevant benchmark depends on the instrument and country being discussed.

Why can a currency fall after a rate rise?#

The rise may have been expected, the economy may look weaker, or another country may have become relatively more attractive. The market prices the full policy path, not one announcement. Risk premia can dominate a small interest-rate advantage when investors view one market as materially more uncertain.

How should I compare rates between currencies?#

Look at the rate differential alongside inflation, expected policy, growth and currency risk. The relevant return is the expected return after currency effects, not the headline rate alone. A negative benchmark yield does not mean every asset in that market must have a negative expected return.

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Sources

Figures were checked against these sources before publication. If a rule changes, we update the page and show the new date.

General information, not personal financial advice. Rules depend on your circumstances; check the official source or speak to a regulated adviser before acting.