2.6 Real vs. Nominal GDP

Nominal vs. Real GDP

Nominal GDP measures total output using current-year prices, so it can rise just because prices rise, even if production hasn't changed. Real GDP measures output using constant base-year prices, removing the effect of inflation. Real GDP is the better measure of actual changes in production and living standards over time.

The GDP Deflator

The GDP price deflator measures the overall price level: Deflator = (Nominal GDP ÷ Real GDP) × 100. Rearranging gives Real GDP = (Nominal GDP ÷ Deflator) × 100. A rising deflator between years signals inflation; comparing nominal GDP growth to real GDP growth reveals how much of the change was due to prices vs. actual output.

Why it matters

Using real GDP allows accurate comparisons of economic growth across years, since it holds prices constant at base-year levels. If nominal GDP grows faster than real GDP, prices are rising; if they grow at the same rate, there's no inflation. Policymakers rely on real GDP to judge true economic performance and business cycle position.

Key terms

Nominal GDP

Total output valued at current-year prices; not adjusted for inflation.

Real GDP

Total output valued at constant base-year prices; adjusted for inflation.

GDP Price Deflator

(Nominal GDP ÷ Real GDP) × 100; measures the overall price level relative to the base year.

Base year

The reference year whose prices are used to calculate real GDP; nominal GDP = real GDP in this year.

Why use real GDP?

It isolates changes in actual production from changes in prices, giving an accurate measure of economic growth.

Try an AP-style question

What is real GDP?

1. $10 trillion
2. $14.4 trillion
3. $8 trillion
4. $12 trillion