11.2 Exchange Rates


2026 Syllabus Objectives

By the end of these notes, you should be able to:

  1. Explain how exchange rates are measured, including the difference between nominal and real exchange rates, and what a trade-weighted exchange rate is.
  2. Explain how exchange rates are determined under fixed and managed exchange rate systems.
  3. Distinguish between revaluation and devaluation of a fixed exchange rate.
  4. Explain how exchange rates change under different exchange rate systems.
  5. Analyse the effects of changing exchange rates on the external economy using the Marshall-Lerner condition and the J-curve.

Objective 1 — Measuring Exchange Rates

What Is an Exchange Rate?

An exchange rate is simply the price of one country's currency expressed in terms of another country's currency.

For example, if the exchange rate between the British pound and the US dollar is 1 pound = 1.25 dollars, then to buy 1 British pound, you need to hand over 1.25 US dollars.

Exchange rates matter because every time a country imports or exports goods, the currencies of both countries are involved. A change in the exchange rate affects how expensive a country's goods are to foreign buyers, and how expensive foreign goods are to domestic buyers.


Nominal Exchange Rate

The nominal exchange rate is the actual, face-value price of one currency in terms of another. It is the number you see quoted at a bank or an airport currency exchange.

  • Example: 1 British pound = 1.25 US dollars today. This is the nominal exchange rate.
  • It does not account for inflation (inflation means prices rising over time).

So the nominal exchange rate tells you the raw number, but it doesn't tell you how much purchasing power (buying power) you actually have.


Real Exchange Rate

The real exchange rate adjusts the nominal exchange rate to account for differences in price levels (the general level of prices) between two countries.

In simple terms: the real exchange rate tells you how many goods and services in one country you can exchange for goods and services in another country.

Formula:

Real Exchange Rate = Nominal Exchange Rate × (Domestic Price Level ÷ Foreign Price Level)

Why does it matter?

Imagine the nominal exchange rate stays the same between Country A and Country B, but prices in Country A rise much faster than in Country B. Country A's goods become more expensive in real terms, even though the exchange rate number hasn't changed. The real exchange rate captures this.

  • If a country's real exchange rate rises, its goods become relatively more expensive abroad → exports become less competitive.
  • If a country's real exchange rate falls, its goods become relatively cheaper abroad → exports become more competitive.

Key Distinction:

Nominal Exchange RateReal Exchange Rate
What it showsThe face-value price of one currency in anotherThe adjusted rate accounting for price level differences
Accounts for inflation?NoYes
Used forDay-to-day currency transactionsComparing international competitiveness

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