Real Effective Exchange Rate (REER)

What Is the Real Effective Exchange Rate?

The real effective exchange rate, commonly abbreviated as REER, is a measure of a country's currency value that accounts for both the pattern of its trade relationships and the differences in price levels between it and its trading partners. It answers a deceptively simple question: is the currency cheap or expensive relative to the currencies of the countries with which it trades, after adjusting for differences in inflation? A bilateral exchange rate — say, the domestic currency against the US dollar — captures only one dimension of international competitiveness. The REER captures all of them simultaneously, weighting each trading partner's currency by its share of the country's trade.

When the REER rises, or appreciates, domestic goods and services become relatively more expensive in international markets. Exporters lose competitiveness, imports become cheaper, and the trade balance tends to deteriorate, other things being equal. When the REER falls, or depreciates, the opposite occurs: domestic production becomes relatively cheaper, exports gain competitiveness, and the trade balance tends to improve.

The REER is therefore one of the most important prices in an open economy. It influences the allocation of resources between tradeable and non-tradeable sectors, shapes the current-account balance, and transmits monetary-policy actions and commodity-price shocks across borders. International organisations such as the International Monetary Fund use REER measures extensively in their assessment of whether a country's currency is overvalued or undervalued relative to macroeconomic fundamentals.

How It Is Calculated

The REER is constructed in two stages. First, the nominal effective exchange rate (NEER) is computed as a trade-weighted geometric average of bilateral exchange rates:

$\text{NEER}_t = \prod_{j=1}^{N} \left(\frac{e_{j,t}}{e_{j,0}}\right)^{w_j}$

where $e_{j,t}$ is the bilateral nominal exchange rate against trading partner $j$ at time $t$ (expressed as units of foreign currency per unit of domestic currency, so that an increase means appreciation), $e_{j,0}$ is the base-period value, $w_j$ is the trade weight assigned to partner $j$, and $N$ is the number of trading partners. The weights sum to one and are typically based on merchandise trade shares, although some constructions incorporate services trade as well.

Second, the NEER is adjusted for relative price levels to obtain the REER:

$\text{REER}_t = \text{NEER}_t \times \frac{P_t}{\prod_{j=1}^{N} P_{j,t}^{w_j}}$

where $P_t$ is the domestic price index and $P_{j,t}$ is the price index of trading partner $j$. The ratio of the domestic price level to the trade-weighted foreign price level captures the inflation differential. If domestic inflation exceeds that of trading partners, the REER appreciates even if the nominal exchange rate does not move, because domestic goods have become relatively more expensive.

Choice of Price Index

The price index used matters. Consumer price indices are the most common choice because they are available at monthly frequency for nearly every country, but unit labour cost indices are sometimes preferred for competitiveness analysis because they more directly reflect the cost of production. The Bank for International Settlements publishes REER series using both CPI and producer price deflators.

Index Format

The REER is expressed as an index number, typically set to 100 in a chosen base year. A value of 110 means the currency is ten per cent more expensive in real trade-weighted terms than it was in the base year; a value of 90 means it is ten per cent cheaper.

How to Read the Numbers

Interpreting the REER requires caution. Not all appreciation is harmful, and not all depreciation is beneficial. A currency may appreciate in real terms because productivity in the tradeable sector is growing faster than in trading-partner economies — the Balassa-Samuelson effect — which does not imply a loss of competitiveness. Conversely, a real depreciation caused by a collapse in commodity prices or a loss of investor confidence is hardly a welcome development even if it boosts export volumes.

Economic Significance

The REER is central to the concept of external balance. The International Monetary Fund's External Balance Assessment framework uses model-based estimates of the equilibrium REER to determine whether a country's exchange rate is consistent with its economic fundamentals and desirable policies. Deviations from the estimated equilibrium — referred to as currency misalignment — can have significant policy implications, including recommendations for fiscal adjustment, structural reform, or changes in exchange-rate management.

For commodity-exporting economies, the REER is heavily influenced by the terms of trade. When the price of a dominant export commodity rises, the currency tends to appreciate in both nominal and real terms, squeezing the non-commodity tradeable sector. This phenomenon, sometimes called "Dutch disease," can lead to deindustrialisation and concentration of the economy in the resource sector. Monitoring the REER helps policymakers identify the onset and severity of such dynamics.

Monetary-policy transmission in open economies runs partly through the exchange rate. When a central bank raises the policy rate, the currency typically appreciates — both nominally and in real terms — making imports cheaper and dampening inflation directly through the imported-goods channel. The REER captures this channel comprehensively, incorporating the effect across all trading partners rather than focusing on a single bilateral rate.

For multinational corporations and exporters, the REER is a key strategic variable. A sustained real appreciation signals that production costs in the home country are rising relative to competitors, potentially justifying a shift of manufacturing capacity abroad. A real depreciation, meanwhile, may make the home country a more attractive production base. Supply-chain decisions that span multiple countries are often informed by REER trends.

The REER also has important implications for inflation dynamics in open economies. When the REER appreciates, imported goods become cheaper in domestic-currency terms, exerting downward pressure on consumer prices — a disinflationary effect that central banks must account for when calibrating monetary policy. When the REER depreciates, the pass-through from higher import prices can push inflation above target, potentially forcing the central bank to tighten monetary policy at a time when the underlying economy may already be weakening. This tension between the competitiveness-enhancing effects of depreciation and its inflationary consequences is one of the most persistent dilemmas facing policymakers in small open economies.

Over the very long run, REER movements tend to reflect structural shifts in productivity, demographics, and the terms of trade. Economies with rapid productivity growth in their tradeable sectors tend to experience real appreciation as rising wages in the export sector spill over into the non-tradeable sector without a corresponding increase in productivity — the Balassa-Samuelson mechanism. Ageing economies, by contrast, may see sustained real depreciation as their labour forces shrink and domestic demand weakens relative to their trading partners.

Related Indicators

• Terms of Trade — relative export and import prices that strongly influence the REER, especially for commodity exporters
• Current Account to GDP — external balance outcome that the REER helps to determine
• CAD/USD Exchange Rate — the most closely watched bilateral rate for the Canadian dollar
• Unit Labour Costs — alternative deflator for competitiveness-focused REER measures