What Is the Real Exchange Rate?

The real exchange rate (RER) measures the relative price of goods between two countries, adjusting for differences in price levels. It is a fundamental concept in international economics that reflects the purchasing power of one country's currency relative to another after accounting for inflation. Unlike the nominal exchange rate, which simply expresses how much one currency is worth in terms of another, the real exchange rate provides insight into competitiveness and the true value of a currency when used to buy goods and services across borders.

Formula and Calculation

The real exchange rate is typically calculated using the following formula:

RER = (Nominal Exchange Rate × Foreign Price Level) / Domestic Price Level

In this equation:

• The nominal exchange rate is defined as the amount of domestic currency needed to purchase one unit of foreign currency.
• The foreign price level is a measure of prices in the other country, often based on a consumer price index (CPI) or a producer price index (PPI).
• The domestic price level reflects the price of goods and services within the home country, also measured using a CPI or PPI.

For example, if the nominal exchange rate is 1.2 USD per euro, the European price level index is 110, and the U.S. price level index is 100, then the real exchange rate is:

RER = (1.2 × 110) / 100 = 1.32

This result implies that, after adjusting for price differences, European goods are relatively more expensive in dollar terms.

Interpretation and Importance

A real exchange rate greater than 1 generally means that foreign goods are relatively more expensive than domestic goods, indicating a loss in competitiveness for the foreign economy or an advantage for the domestic economy. Conversely, a real exchange rate less than 1 suggests that foreign goods are cheaper, which may make domestic industries less competitive internationally.

The real exchange rate plays a central role in determining trade flows. When a country’s real exchange rate depreciates, its exports become more affordable to foreigners, while imports become more expensive for domestic consumers. This can lead to an improvement in the trade balance. Conversely, a real appreciation can hinder exports and increase imports, potentially leading to a trade deficit.

Real vs. Nominal Exchange Rate

While the nominal exchange rate is determined by foreign exchange markets and reflects the value of currencies in isolation, the real exchange rate captures the broader economic context by including inflation or price level changes. As such, two countries might have a stable nominal exchange rate, but their real exchange rate could still change significantly if one country experiences high inflation and the other does not.

This distinction is crucial for understanding how currency values affect real economic outcomes. For instance, even if a country's nominal exchange rate remains constant, an increase in its domestic price level relative to trading partners will make its goods more expensive abroad, resulting in a real appreciation.

Role in Economic Policy

Monetary and fiscal policymakers monitor the real exchange rate as a gauge of external competitiveness. A persistently overvalued real exchange rate can hurt exporters, reduce foreign demand for domestic goods, and slow economic growth. On the other hand, a significantly undervalued real exchange rate might suggest a country is artificially suppressing its currency to boost exports, often leading to trade tensions.

Exchange rate misalignments, as revealed by shifts in the real exchange rate, are also a focus of international institutions such as the International Monetary Fund (IMF). These institutions may use real exchange rate indicators to assess whether a country’s currency is over- or undervalued and whether its current account balance is sustainable.

Real Effective Exchange Rate (REER)

A related concept is the real effective exchange rate (REER), which expands the idea of the real exchange rate to include a trade-weighted basket of currencies. The REER takes into account the country’s trading partners and adjusts for inflation differences across multiple countries, providing a more comprehensive view of overall competitiveness.

While the RER measures bilateral competitiveness (between two countries), the REER is broader and more informative for countries engaged in trade with multiple partners.

Limitations

Despite its usefulness, the real exchange rate has limitations. It depends heavily on the accuracy of price indices, which may not reflect identical baskets of goods across countries. Moreover, non-traded goods and services—those that are not part of international trade—can distort interpretations, especially when comparing economies with very different structures.

In addition, the real exchange rate does not capture short-term exchange rate fluctuations driven by capital flows, speculation, or central bank interventions. For that reason, it is often used in conjunction with other metrics for a fuller understanding of a country’s economic position.

The Bottom Line

The real exchange rate offers a more meaningful measure of a currency’s value than its nominal counterpart by incorporating price level differences. It provides essential insights into a country’s international competitiveness, influences trade flows, and informs economic policy decisions. While it has some limitations, especially concerning data accuracy and scope, the real exchange rate remains a vital tool for evaluating exchange rate dynamics in a globalized economy.