When talking about economic growth, it's not always clear: is it real growth or just that goods have become more expensive? Here, one indicator called the implicit price deflator helps clarify the picture.

Basically, the GDP deflator shows by what percentage prices for everything produced in the country have changed. It is a key tool for separating real economic growth from just rising prices of goods and services. Nominal GDP can increase simply because everything is getting more expensive, while real GDP shows whether the economy is truly developing or if inflation is just happening.

How does this work in practice? Take the nominal GDP (the total value at current prices) and divide it by the real GDP (the total value at base year prices), then multiply by 100. This is the simplest form of the GDP deflator formula: GDP Deflator = (Nominal GDP / Real GDP) × 100.

What do the numbers mean? If the deflator equals 100, it means prices haven't changed. If above 100 — inflation has occurred, prices have risen. If below — deflation, prices have fallen. To find the percentage change, simply subtract 100 from the resulting value.

Let's take a specific example. Suppose the nominal GDP in 2024 is $1.1 trillion, and the real GDP (at 2023 prices) is $1 trillion. Using the formula: (1.1 / 1) × 100 = 110. This indicates that prices have increased by 10% over the year.

So, the GDP deflator and its formula are ways to see the real picture of the economy, removing the noise of inflation. Economists use this constantly to understand whether the economy is truly growing or just getting more expensive.