Components of Gross Domestic Product by Expenditure

Here is a description of each GDP component:

C (consumption) is normally the largest GDP component in the economy, consisting of private expenditures in the economy (household final consumption expenditure). These personal expenditures fall under one of the following categories: durable goods, nondurable goods, and services. Examples include food, rent, jewelry, gasoline, and medical expenses, but not the purchase of new housing.
I (investment) includes, for instance, business investment in equipment, but does not include exchanges of existing assets. Examples include construction of a new mine, purchase of software, or purchase of machinery and equipment for a factory. Spending by households (not government) on new houses is also included in investment. In contrast to its colloquial meaning, "investment" in GDP does not mean purchases of financial products. Buying financial products is classed as 'saving', as opposed to investment. This avoids double-counting: if one buys shares in a company, and the company uses the money received to buy plant, equipment, etc., the amount will be counted toward GDP when the company spends the money on those things; to also count it when one gives it to the company would be to count two times an amount that only corresponds to one group of products. Buying bonds or companies' equity shares is a swapping of deeds, a transfer of claims on future production, not directly an expenditure on products; buying an existing building will involve a positive investment by the buyer and a negative investment by the seller, netting to zero overall investment.
G (government spending) is the sum of government expenditures on final goods and services. It includes salaries of public servants, purchases of weapons for the military and any investment expenditure by a government. It does not include any transfer payments, such as social security or unemployment benefits. Analyses outside the USA will often treat government investment as part of investment rather than government spending.
X (exports) represents gross exports. GDP captures the amount a country produces, including goods and services produced for other nations' consumption, therefore exports are added.
M (imports) represents gross imports. Imports are subtracted since imported goods will be included in the terms G, I, or C, and must be deducted to avoid counting foreign supply as domestic.
Note that C, I, and G are expenditures on final goods and services; expenditures on intermediate goods and services do not count. (Intermediate goods and services are those used by businesses to produce other goods and services within the accounting year.) So for example if a car manufacturer buys auto parts, assembles the car and sells it, only the final car sold is counted towards the GDP. Meanwhile, if a person buys replacement auto parts to install them on their car, those are counted towards the GDP.

According to the U.S. Bureau of Economic Analysis, which is responsible for calculating the national accounts in the United States, "In general, the source data for the expenditures components are considered more reliable than those for the income components."

Encyclopedia Britannica records an alternate way of measuring exports minus imports: notating it as the single variable NX.[23
Provide a bulleted overview of the components of GDP by expenditure
The following are the five components of GDP by expenditure:
- Consumption: Private expenditures in the economy
- Investment: Includes business investments, but not exchanges of assets
- Government Spending: Sum of government spend on goods and services
- Exports: Gross exports
- Imports: Gross imports