Lesson 5.3: Exchange Rates

Lesson Overview

If you’ve ever traveled, bought something online from another country, or watched the news mention “a strong dollar,” you’ve encountered exchange rates. An exchange rate is simply the price of one currency in terms of another.

Exchange rates matter because they change the relative prices of goods, services, and investments across countries. A currency that becomes more valuable (an appreciation) makes imports cheaper and exports more expensive. A currency that becomes less valuable (a depreciation) tends to do the opposite.

In this lesson, you’ll learn how exchange rates are quoted, what moves them in the short run and long run, and the key differences between floating and fixed exchange rate systems.

Learning Objectives

• Define an exchange rate and interpret common currency quotes.
• Explain appreciation and depreciation and their effects on trade and inflation.
• Describe how currency markets work using supply and demand for currencies.
• Identify key drivers of exchange rates: interest rates, inflation expectations, growth, and risk sentiment.
• Explain the difference between floating, pegged, and fixed exchange rate systems.
• Understand why central banks intervene and what it costs (foreign reserves, credibility, policy tradeoffs).
• Use simple examples to connect exchange rates to everyday prices and business decisions.

What Is an Exchange Rate?

An exchange rate is the price of one currency in terms of another. For example:

• USD/EUR = 0.92 can be read as “1 U.S. dollar buys 0.92 euros.”
• USD/JPY = 150 can be read as “1 U.S. dollar buys 150 Japanese yen.”
• EUR/USD = 1.09 can be read as “1 euro buys 1.09 U.S. dollars.”

Quotes can be confusing because they flip depending on how they’re written. The key is to read them like a fraction: the first currency is priced in the second currency.

Appreciation and Depreciation

Appreciation

A currency appreciates when it becomes more valuable relative to another currency. If the dollar appreciates against the euro, you get more euros per dollar.

Depreciation

A currency depreciates when it becomes less valuable relative to another currency. If the dollar depreciates against the euro, you get fewer euros per dollar.

Why This Matters: The Price Channel

• Stronger currency → imports cheaper, exports more expensive (foreign buyers see higher prices).
• Weaker currency → imports more expensive, exports cheaper.

This is one reason exchange rates can influence inflation: a weaker currency can raise the local-currency price of imported goods (fuel, electronics, food inputs), pushing prices up.

Who Demands and Supplies Currency?

Currencies trade in global markets (often called the foreign exchange or “forex” market). The market is huge and decentralized—banks, firms, investors, governments, and individuals exchange currencies for many reasons.

Demand for a Currency Comes From

• Buying exports: foreigners need your currency to buy your goods/services.
• Investing: foreigners buy your stocks, bonds, real estate, or start businesses.
• Speculation and hedging: traders expect the currency to rise or want to reduce risk.
• Safe-haven flows: during crises, investors may rush into currencies seen as stable.

Supply of a Currency Comes From

• Buying imports: your residents sell your currency to buy foreign goods/services.
• Investing abroad: your residents buy foreign assets and need foreign currency.
• Speculation and hedging: traders sell when they expect the currency to fall or to manage exposure.

Just like any market: if demand for a currency rises (relative to supply), its price tends to rise (appreciate). If supply rises (relative to demand), its price tends to fall (depreciate).

Four Big Drivers of Exchange Rates

Exchange rates move for many reasons, but these four show up repeatedly in real-world explanations.

1) Interest Rates

Higher interest rates (or expectations of higher future rates) can attract foreign capital seeking better returns. More capital inflow increases demand for the currency, which can lead to appreciation.

Important nuance: exchange rates react to expectations. If higher rates are already expected, the move may be priced in.

2) Inflation and Purchasing Power

If a country has persistently higher inflation than its trading partners, its goods become relatively more expensive over time. In the long run, that tends to push the currency toward depreciation.

3) Economic Growth and Productivity

Strong growth can attract investment and raise currency demand. In the long run, higher productivity can support a stronger currency, especially if it boosts exports and investment opportunities.

4) Risk, Uncertainty, and “Safe Haven” Demand

In global stress events, investors may move into assets perceived as safer, which can strengthen certain currencies. When risk appetite returns, flows can reverse.

Short Run vs. Long Run: Two Helpful Lenses

Short Run (months to a few years)

Exchange rates are often dominated by financial flows, expectations, interest rate news, and shifting risk sentiment. That can create large swings—even when trade flows change slowly.

Long Run (years to decades)

Differences in inflation, productivity, and economic fundamentals tend to matter more. A classic long-run idea is purchasing power parity (PPP): if the same basket of goods is cheaper in one country than another, over time exchange rates should move toward equalizing prices.

PPP is not a perfect law (shipping costs, taxes, local services, and product differences matter), but it is a useful intuition: persistent price differences tend to create pressure for exchange rate adjustment over long horizons.

Exchange Rate Systems: Floating vs. Fixed

Countries choose different exchange rate regimes—rules for how their currency’s value is set.

1) Floating Exchange Rates

Under a floating system, the exchange rate is mostly determined by market supply and demand. Central banks may influence it indirectly through interest rate policy, and occasionally intervene, but there is no fixed target.

• Pros: automatic adjustment to shocks; independent monetary policy.
• Cons: volatility can hurt trade and investment planning; currency swings can amplify crises.

2) Pegged or Fixed Exchange Rates

Under a fixed or pegged system, the government commits to keeping the currency at a target value (or within a narrow band) against another currency (or a basket of currencies).

• Pros: more stable prices for international trade; can anchor inflation expectations.
• Cons: requires foreign reserves and credibility; limits independent monetary policy.

How a Peg Is Maintained

If a country wants to prevent its currency from falling below a peg, it must create demand for its currency. One common method is selling foreign reserves and buying its own currency.

If reserves run low, the peg can become unsustainable, which can lead to a sharp devaluation.

The “Policy Tradeoff” Behind Fixed Exchange Rates

A simplified but powerful idea: it is hard to have all three of these at the same time:

• Stable (fixed) exchange rate
• Free cross-border capital flows
• Independent monetary policy (setting interest rates for domestic goals)

Many countries can choose two, but not all three at once. This is why fixed exchange rates often come with either capital controls or a willingness to align interest rates with the anchor currency’s policy.

Exchange Rates and Everyday Life

Imports and Consumer Prices

If your currency strengthens, imported electronics, fuel, and raw materials can become cheaper. If your currency weakens, those items often become more expensive, which can push up overall inflation.

Exports and Jobs

A stronger currency can make exports less competitive abroad, which may reduce export growth. A weaker currency can boost export competitiveness—but also raises costs for imported inputs.

Travel and Online Shopping

When your currency appreciates, your vacation abroad feels cheaper. When it depreciates, the same trip costs more in your currency.

Businesses and Risk Management

Firms that buy inputs abroad or sell products internationally face currency risk. Many use financial contracts (like forward contracts) to hedge and stabilize costs and revenues.

Practice: Check Your Understanding

1. If USD/EUR rises from 0.90 to 0.95, did the dollar appreciate or depreciate against the euro? Explain in one sentence.
2. Name one way a stronger currency affects:
   • Import prices
   • Export competitiveness
3. List two sources of demand for a currency and two sources of supply for a currency.
4. Why might higher interest rates lead to currency appreciation (at least in the short run)?
5. A country pegs its currency to the dollar but runs out of foreign reserves. What risk does it face?

Reflection Prompt

Think about a product you use that relies on imports (fuel, a smartphone, a car part, coffee, medicine).

• If your currency suddenly depreciated 15%, which prices in your life might rise first?
• Who would benefit from a weaker currency? Who would be hurt?
• Why might a government still prefer a stable peg even if it limits policy flexibility?

What’s Next?

In Lesson 5.4: Global Financial Flows, we’ll connect exchange rates to the movement of capital: foreign direct investment, portfolio flows, and why money can cross borders quickly—sometimes stabilizing economies, sometimes destabilizing them.