Real Exchange Rate vs Nominal Rate: Example

The nominal exchange rate is what you see quoted on the currency market—say, 1 USD = 1.10 EUR—while the real exchange rate adjusts for inflation differences between the two countries. A simple worked example shows why: if the dollar buys less in the US than the euro buys in Europe (due to higher US inflation), the real exchange rate reflects that loss of purchasing power, even if the nominal rate hasn’t moved.

Nominal Rate: The Market Quote

Every day, currency markets publish nominal exchange rates. If you travel or trade internationally, you see them directly: 1 USD = 1.10 EUR, 1 GBP = 1.25 USD, 1 JPY = 0.0067 USD. These are the rates at which buyers and sellers meet in the spot market. They reflect real-time supply and demand, interest rate differentials, and market expectations.

The nominal rate is concrete and unambiguous. It tells you how many euros you get per dollar at a particular moment. It does not, however, tell you whether a dollar is becoming stronger or weaker in real economic terms.

Real Rate: Inflation-Adjusted Power

The real exchange rate strips away inflation to reveal the true purchasing power. It answers a different question: Given that prices are rising in both countries, how much can a dollar actually buy in Europe versus at home?

Here is the formula:

Real Exchange Rate = Nominal Rate × [(1 + Inflation Rate_Country 2) / (1 + Inflation Rate_Country 1)]

If we express this as an index (say, base year = 100), the real rate moves if either the nominal rate changes or the inflation gap widens.

A Worked Example

Suppose we’re comparing the USD to the EUR over one year.

Year 0 (baseline):

• Nominal rate: 1 USD = 1.00 EUR
• Real rate index: 100 (both at baseline)

Year 1:

• US inflation: 4% (prices in the US rise 4%)
• Eurozone inflation: 2% (prices in the Eurozone rise 2%)
• Nominal rate: 1 USD = 1.00 EUR (unchanged by the market)

At first glance, the dollar hasn’t moved—the nominal rate is still 1:1. But inflation has eroded the dollar’s value at home. What cost $100 a year ago now costs $104. In the Eurozone, what cost €100 now costs €102.

Computing the real rate:

Real Rate Index (Year 1) = 100 × [(1 + 0.02) / (1 + 0.04)] = 100 × (1.02 / 1.04) = 100 × 0.9808 = 98.08

The real exchange rate fell from 100 to 98.08. Even though the nominal rate didn’t budge, the dollar has weakened in real terms. A dollar is now worth less in real purchasing power relative to the euro because the US experienced higher inflation.

Why This Matters: A Practical Scenario

Imagine an American exporter selling machinery to Europe. A year ago, the company quoted a machine at $100,000 (1 EUR = 1 USD equivalent). The euro customer paid €100,000.

Now the company wants to quote the same machine. If it maintains the same nominal USD price ($100,000) and the nominal rate is still 1:1, the customer still pays €100,000. But:

• The US company’s costs (labor, materials) have risen 4%, so its cost to produce is higher.
• The European competitor’s costs have risen only 2%.
• In real terms, the American exporter has lost price competitiveness.

Alternatively, if the exporter wants to maintain real (inflation-adjusted) margin, it must raise the USD price to account for the 4% inflation it bore. But then the euro price rises beyond €100,000, and the European customer may shop elsewhere.

This is why the real exchange rate matters more than the nominal rate for trade flows. The nominal rate was stable; the real rate deteriorated. US exports become harder to sell, and imports from Europe become relatively more attractive to US consumers.

Another Scenario: Nominal Movement with Stable Real Rate

Now suppose inflation in both countries is identical (say, 3% each).

Year 1 (scenario 2):

• US inflation: 3%
• Eurozone inflation: 3%
• Nominal rate: 1 USD = 0.95 EUR (the dollar weakened)

Real Rate Index = 100 × [(1 + 0.03) / (1 + 0.03)] = 100 × 1.0 = 100

Even though the nominal rate moved (the dollar depreciated from 1.00 to 0.95), the real rate stayed at 100. Both countries experienced identical inflation, so their relative purchasing power did not change. The nominal depreciation simply reflects symmetry in inflation.

This illustrates a key insight: if two countries have the same inflation rate, their nominal exchange rate movement should (in theory) not affect the real rate. The nominal rate adjusts to “cancel out” symmetric inflation—that is the logic behind purchasing power parity.

Real Rates and Trade Competitiveness

Economists and central banks track real exchange rate indices to assess trade competitiveness. If a country’s real exchange rate rises over time (its currency strengthens in real terms), exports become harder to sell and imports become cheaper, widening the trade deficit. If the real rate falls (the currency weakens in real), exports become more attractive and imports less so.

A central bank managing monetary policy must distinguish between nominal moves and real moves. A nominal depreciation might be desirable if it offsets domestic inflation and keeps the real rate stable. But if the nominal rate is stable while inflation diverges, the real rate deteriorates and trade competitiveness worsens.

Longer-Term Indices

Real exchange rate indices are often calculated as cumulative changes over years or decades, smoothed to show structural trends rather than daily volatility. The US Federal Reserve and international organizations publish real effective exchange rates (REERs) that track one currency against a basket of trading partners, inflation-adjusted. These tell a story: has the dollar strengthened or weakened in real terms relative to competitors? That story guides policy and trade forecasts.

See also