How the GDP Calculator Works
Gross domestic product (GDP) is the value of all the final goods and services that a country makes in a year. It is the most common measure of the size of an economy. There are three ways to measure it, and the most common one adds up all the spending on what is made. This is the expenditure approach, and it is what the GDP Calculator uses.
The formula
GDP = C + I + G + (X - M)
- C, consumer spending: what households spend on goods and services, from food and rent to phone bills and haircuts. It is usually the biggest part.
- I, investment: what businesses spend on equipment, buildings and software, what households spend on new homes, and the change in the stocks that businesses hold. It does not mean buying shares or bonds.
- G, government spending: what the government buys, such as roads, schools, defense and the pay of public workers. Transfers such as pensions and benefits are not counted, because nothing is made when they are paid.
- X, exports: what the country sells to other countries.
- M, imports: what the country buys from other countries. They are taken away, because the spending on them is already in C, I and G but the goods were not made at home.
- X - M, net exports: a positive number is a trade surplus, and a negative number is a trade deficit.
Worked example
| Part | Amount | Share of GDP |
|---|---|---|
| Consumer spending (C) | 10,000 | 63.3% |
| Investment (I) | 3,000 | 19.0% |
| Government spending (G) | 2,500 | 15.8% |
| Net exports (1,500 - 1,200) | 300 | 1.9% |
| GDP | 15,800 | 100% |
Each block of the chart is about 1.6 percentage points.
Consumption ████████████████████████████████████████ 63.3% Investment ████████████ 19.0% Government ██████████ 15.8% Net exports █ 1.9%
An example with a trade deficit
These numbers are in trillions and are only an example: C = 16.2, I = 4.1, G = 3.5, X = 2.3 and M = 3.1. Net exports are 2.3 - 3.1 = -0.8, so GDP = 16.2 + 4.1 + 3.5 - 0.8 = 23.0 trillion. The deficit takes away 3.5% of GDP. Each block is about 1.8 percentage points, and red means a negative part.
Consumption ████████████████████████████████████████ 70.4% Investment ██████████ 17.8% Government █████████ 15.2% Net exports ██ -3.5%
Growth and GDP per person
If you enter the GDP of the year before, the calculator finds the growth:
growth = (GDP now - GDP before) / GDP before x 100
If you enter the population in millions, it finds the GDP per person:
GDP per person = GDP / population
Example: a GDP of 23 trillion and a population of 333 million gives about 69,000 per person. In the example above, if the year before had a GDP of 24.1 trillion, the growth would be -4.6%. Both boxes are optional, and they use the same units as the other numbers.
Nominal and real GDP
This calculator gives nominal GDP, which uses the prices of the year. When prices rise, nominal GDP rises even if the country does not make more. Real GDP is changed to remove the effect of prices, so it is better for comparing years. To find it, divide the nominal GDP by a price index (the GDP deflator) and multiply by 100.
Tips
- Use the same unit and the same period for every number. For example, billions of dollars for one year. Then choose the scale in the calculator.
- Enter investment as a plain number. It can be negative when businesses use up their stocks, and it is the only part that can be.
- Do not count things twice. Count only final goods. The steel in a car is part of the price of the car.
- Use the data of a statistics office for real countries, such as the national accounts of your country or of an international body.
What this calculator does not include
- The income approach and the production approach, which measure the same GDP in other ways.
- Real GDP, inflation, and changes of the exchange rate.
- The things that GDP leaves out, such as unpaid work at home, the black market and damage to the environment. GDP is not a measure of well-being.
This tool is for study and general information. It uses the numbers that you enter, and the example numbers are not real data.