Changes in Exchange Rates and Net Exports — AP Macroeconomics Study Guide

For: AP Macroeconomics candidates sitting AP Macroeconomics.

Covers: The causal relationship between exchange rate changes and net exports, currency appreciation/depreciation effects on import and export prices, foreign exchange market shifts, and the connection between net exports and aggregate demand in open economies.

You should already know: How to draw and interpret the foreign exchange market model. The definition of net exports and nominal vs. real exchange rates. How changes in spending components shift aggregate demand.

A note on the practice questions: All worked questions in the "Practice Questions" section below are original problems written by us in the AP Macroeconomics style for educational use. They are not reproductions of past College Board / Cambridge / IB papers and may differ in wording, numerical values, or context. Use them to practise the technique; cross-check with official mark schemes for grading conventions.

1. What Is Changes in Exchange Rates and Net Exports?

This topic explores how changes in the value of a country’s currency (relative to other currencies) alter the quantity of exports sold abroad and imports purchased domestically, which in turn impacts net exports ($NX=\text{Exports}-\text{Imports}$), a core component of aggregate demand. Per the official AP Macroeconomics Course and Exam Description (CED), this topic is part of Unit 6 and contributes approximately 5-10% of the total exam score. It appears on both multiple-choice (MCQ) and free-response (FRQ) sections, often combined with foreign exchange market graphing or aggregate demand/aggregate supply analysis.

The core intuition is straightforward, but the AP exam frequently tests both directions of causality (exchange rate changes affecting net exports, and net export changes affecting exchange rates) as well as connections to domestic macroeconomic outcomes. This relationship is the foundation for all open-economy policy analysis, making it a high-frequency topic for full-point FRQ questions.

2. How Exchange Rate Changes Affect Export and Import Prices and Net Exports

The first step to analyzing this relationship is connecting exchange rate changes to the prices buyers actually pay. Following AP Macroeconomics convention, we define the nominal exchange rate $e$ as the number of units of foreign currency you can buy with one unit of domestic currency. If $e$ rises, domestic currency has appreciated: 1 U.S. dollar buys more Japanese yen, for example, if the U.S. is the domestic economy. If $e$ falls, domestic currency has depreciated.

Take a domestically produced t-shirt that costs $10 in the U.S. How much does a Japanese consumer pay in yen? The price is $10\times e$ yen. If the dollar appreciates, $e$ goes up, so the yen price of the U.S. t-shirt rises: Japanese consumers will buy fewer U.S. exports. Now reverse that: a Japanese car costs 1,000,000 yen. How much does an American consumer pay in dollars? The price is $\frac{1,000,000}{e}$ dollars. If the dollar appreciates ($e$ rises), the dollar price of the Japanese car falls: American consumers buy more Japanese imports.

Generalizing this relationship:

• Domestic currency appreciation ($\uparrow e$): Exports ↓, Imports ↑, so Net Exports $NX=X-M$ ↓
• Domestic currency depreciation ($\downarrow e$): Exports ↑, Imports ↓, so Net Exports $NX$ ↑

This holds for real exchange rates (adjusted for inflation) as well, as long as relative price levels are constant.

Worked Example

A Canadian wine bottle costs 20 CAD. The U.S. is the domestic economy, with an initial exchange rate of 1 USD = 1.33 CAD. If the USD appreciates so that 1 USD = 1.5 CAD, what happens to the USD price of the wine for U.S. consumers, and how does this change U.S. net exports, ceteris paribus?

1. Calculate the initial USD price: $P_{USD}=\frac{\text{Price in CAD}}{e}=\frac{20}{1.33}\approx \$15$
2. Calculate the new USD price after appreciation: $P_{new}=\frac{20}{1.5}\approx \$13.33$
3. Identify the effect on imports: The lower USD price means U.S. consumers will buy more Canadian wine, so U.S. imports from Canada increase.
4. Identify the net export effect: Since $NX=X-M$, higher $M$ means U.S. net exports decrease, ceteris paribus.

Exam tip: Always confirm the exchange rate convention before solving: if a question defines $e$ as domestic currency per foreign currency, reverse the relationship above. AP problems almost always use foreign currency per domestic currency, but double-check to avoid reversed logic.

3. Reverse Causality: How Changes in Net Exports Affect Exchange Rates

AP exams do not only test how exchange rates change net exports: they also regularly test the reverse direction: exogenous changes in net exports (changes unrelated to exchange rates) shift demand or supply for currency in the foreign exchange market, changing the equilibrium exchange rate.

Recall the foreign exchange (forex) market model for domestic currency: the y-axis is the exchange rate $e$ (foreign currency per domestic currency), demand for domestic currency comes from foreigners who want to buy domestic exports or assets, and supply of domestic currency comes from domestic consumers who want to buy foreign imports or assets. If foreign demand for domestic exports increases exogenously (for example, foreign consumers develop a new preference for domestic organic cocoa), foreigners need more domestic currency to buy these exports. This shifts the demand curve for domestic currency to the right, increasing the equilibrium $e$, which means domestic currency appreciates.

Conversely, if domestic demand for foreign imports increases exogenously (for example, domestic consumers start buying more foreign electric cars), domestic consumers need more foreign currency, so they supply more domestic currency to the forex market. This shifts the supply curve for domestic currency right, decreasing equilibrium $e$, so domestic currency depreciates.

Worked Example

Exogenous change: Chinese consumers increase their demand for Australian beef, ceteris paribus, with the Australian dollar (AUD) as the domestic currency. How does this change affect the equilibrium exchange rate for AUD, and will AUD appreciate or depreciate?

1. Identify the change in currency demand: Higher Chinese demand for Australian exports means Chinese buyers need more AUD to purchase the beef, so demand for AUD in the forex market increases.
2. Describe the shift: The original equilibrium is the intersection of initial demand $D_1$ and supply $S$ for AUD. Demand shifts right from $D_1$ to $D_2$.
3. Find the new equilibrium: The new intersection of $D_2$ and $S$ occurs at a higher value of $e$, where $e$ is Chinese yuan (CNY) per AUD.
4. Interpret the result: A higher $e$ means 1 AUD buys more CNY than before, so the Australian dollar appreciates, ceteris paribus.

Exam tip: When shifting forex curves, always ask: who wants what currency? If foreigners want more domestic goods, they demand domestic currency, not supply it. This is the most common mistake in reverse causality questions.

4. Exchange Rates, Net Exports and Aggregate Demand

Since net exports are one of the four core components of aggregate demand: $$AD=C+I+G+NX$$ any change in net exports from exchange rate changes will shift the entire aggregate demand curve, impacting domestic real GDP and the price level.

The full causal chain for depreciation is: Domestic currency depreciation → $\downarrow e$ → export prices fall for foreigners → exports rise → import prices rise for domestic consumers → imports fall → $\uparrow NX$ → AD shifts right. Rightward AD shift increases short-run real GDP and the aggregate price level, ceteris paribus. For appreciation, the chain reverses: $\uparrow e$ → $\downarrow NX$ → AD shifts left → lower short-run real GDP and price level.

This connection is critical for analyzing the effectiveness of fiscal and monetary policy in open economies, a key follow-up topic in Unit 6. For example, expansionary fiscal policy raises domestic interest rates, attracts foreign capital, appreciates domestic currency, reduces net exports, and crowds out some output — this entire mechanism relies on the exchange rate-net export relationship.

Worked Example

The European Central Bank undertakes expansionary monetary policy, which lowers the euro (EUR) interest rate ceteris paribus. Lower interest rates cause the EUR to depreciate relative to all other currencies. Starting from long-run equilibrium, how does this depreciation affect the euro area AD curve, real GDP, and the price level in the short run?

1. Confirm the effect of depreciation on net exports: EUR depreciation means 1 EUR buys less foreign currency, so European exports are cheaper for foreign buyers, and imports into Europe are more expensive for European consumers.
2. Calculate the change in net exports: Exports increase, imports decrease, so $NX=X-M$ increases.
3. Connect to aggregate demand: Since NX is a component of AD, an increase in NX shifts the entire AD curve right from $A{D}_1$ to $A{D}_2$.
4. Identify the short-run effect: The new short-run equilibrium (intersection with the SRAS curve) occurs at a higher level of real GDP and a higher aggregate price level than the original long-run equilibrium.

Exam tip: When asked to connect exchange rate changes to AD on an FRQ, never skip the intermediate net exports step. AP FRQ rubrics require the explicit chain from exchange rate → NX → AD shift to award full credit.

5. Common Pitfalls (and how to avoid them)

• Wrong move: Assuming that when domestic currency appreciates, both exports and imports decrease, so net exports do not change. Why: Students confuse quantity effects for exports vs. imports; appreciation reduces export quantities but increases import quantities, not both. Correct move: Always separate the effects: appreciation → X↓, M↑ → NX↓; depreciation → X↑, M↓ → NX↑.
• Wrong move: Shifting supply of domestic currency when foreign demand for domestic exports increases. Why: Students mix up who supplies and demands currency in the forex market. Correct move: Whenever exogenous foreign demand for domestic goods increases, foreigners need more domestic currency, so demand for domestic currency shifts right, not supply.
• Wrong move: Claiming that an exogenous increase in net exports causes domestic currency depreciation. Why: Students memorize "depreciation increases NX" and reverse the causal direction incorrectly. Correct move: If NX increases from higher foreign demand for domestic goods, demand for domestic currency rises, leading to appreciation, not depreciation.
• Wrong move: Reversing the effect of appreciation on net exports, i.e., stating appreciation increases NX. Why: Students mix up exchange rate conventions, leading to flipped logic. Correct move: Write the causal chain on scratch paper before answering to confirm: "appreciation = domestic goods more expensive for foreigners → exports fall → NX falls".
• Wrong move: Skipping the net exports step when connecting exchange rate changes to AD shifts on FRQs. Why: Students assume the connection is obvious and do not state the intermediate step. Correct move: Always explicitly write that exchange rate changes alter NX before stating the effect on AD, to meet rubric requirements.

6. Practice Questions (AP Macroeconomics Style)

Question 1 (Multiple Choice)

If the Japanese yen depreciates relative to the US dollar, ceteris paribus, which of the following correctly describes the effect on Japan’s net exports with the US? A) Net exports increase, because Japanese exports to the US are more expensive and US imports into Japan are cheaper. B) Net exports increase, because Japanese exports to the US are cheaper and US imports into Japan are more expensive. C) Net exports decrease, because Japanese exports to the US are more expensive and US imports into Japan are cheaper. D) Net exports decrease, because Japanese exports to the US are cheaper and US imports into Japan are more expensive.

Worked Solution: Depreciation of the yen means 1 yen buys fewer US dollars than before. A Japanese good costs fewer dollars for US consumers, so Japanese exports to the US become cheaper, increasing the quantity of exports. A US good costs more yen for Japanese consumers, so US imports into Japan become more expensive, decreasing the quantity of imports. Since net exports = exports - imports, higher exports and lower imports mean net exports increase. This matches option B. The correct answer is B.

Question 2 (Free Response)

The Indian government runs expansionary fiscal policy that increases domestic interest rates relative to the UK’s interest rate, ceteris paribus. Higher interest rates attract financial capital from the UK to India. (a) Will the Indian rupee (INR) appreciate or depreciate relative to the British pound (GBP)? Explain your answer by referencing the foreign exchange market for INR. (2 points) (b) Given the change in the INR exchange rate you found in (a), what will happen to India’s net exports with the UK? Explain. (2 points) (c) Given the change in net exports you found in (b), how will this affect India’s aggregate demand curve? Will expansionary fiscal policy be more or less effective at increasing real GDP than it would be in a closed economy? Explain. (2 points)

Worked Solution: (a) The Indian rupee will appreciate. Higher relative interest rates in India increase UK demand for Indian assets, so UK buyers need more INR to purchase these assets. This shifts the demand curve for INR right in the foreign exchange market, increasing the equilibrium exchange rate (GBP per INR), which means the INR appreciates. (b) INR appreciation means 1 INR buys more GBP than before. Indian exports to the UK become more expensive for UK consumers, so Indian exports to the UK fall. UK imports into India become cheaper for Indian consumers, so Indian imports from the UK rise. Since $NX=X-M$, falling X and rising M mean India's net exports decrease. (c) Net exports are a component of aggregate demand, so a decrease in net exports shifts the aggregate demand curve left relative to where it would be without the exchange rate change. This offsets some of the rightward AD shift from expansionary fiscal policy, so expansionary fiscal policy is less effective at increasing real GDP in this open economy than it would be in a closed economy.

Question 3 (Application / Real-World Style)

In 2023, the Mexican peso depreciated by 15% against the US dollar. A Mexican car manufactured for export costs 500,000 pesos. Before depreciation, the exchange rate was 20 pesos per 1 USD. After depreciation, the exchange rate is 23 pesos per 1 USD. Calculate the USD price of the car before and after depreciation, and explain how this change affects Mexico’s net exports to the US, holding everything else constant.

Worked Solution: The USD price of the car equals the peso price divided by the exchange rate (pesos per USD). Before depreciation: $$P_{initial}=\frac{500,000}{20}=\$25,000$$ After depreciation: $$P_{new}=\frac{500,000}{23}\approx \$21,739$$ The 15% peso depreciation reduced the USD price of the Mexican export by ~$3,261, making Mexican cars much more affordable for US consumers. US imports of Mexican cars will rise, increasing Mexican exports to the US, while US goods imported into Mexico become more expensive in peso terms, reducing Mexican imports of US goods. This combination leads to an increase in Mexico's net exports with the US, ceteris paribus.

7. Quick Reference Cheatsheet

8. What's Next

This chapter gives you the core causal relationship between exchange rates and net exports that is the foundation for all open-economy policy analysis in AP Macroeconomics. Next, you will apply this relationship to evaluate the effectiveness of fiscal and monetary policy in open economies with floating exchange rates. Without mastering the exchange rate-NX link, you will not be able to explain why monetary policy is more effective and fiscal policy is less effective under floating exchange rates, a common high-weight FRQ topic. This topic also feeds into the larger analysis of how international trade and finance affect domestic output, employment, and inflation, which is the core theme of Unit 6. Follow-up topics to study next: Interest Rates and Foreign Capital Flows Policy Effectiveness in Open Economies Balance of Payments and Currency Systems