GDP Formulas

Expenditure Approach (Used to calculate goods/services)
 GDP = C + Ig + G + Xn

• C - consumption (personal). (Buying)
• Ig - gross private domesticated investment. (Inventory)
• G - government spending
• Xn - net export. (Exports - Imports).

Income Approach (Used to calculate factor of production)

 GDP = W + R + I +P + Statistical Adjustments

• W - wages (salaries/compensation)
• R - rents (rental income)
• I - interest (interest income)
• P - proprietor's income 
• Statistical Adjustments - add to match with the expenditure approach.

Budget

 Transfer payments + Government Purchase Goods & Services  - Government Tax & Fee Collection.

Deficit (+)                 · Surplus (-)

Trade
 Export - Import

Surplus (+)                ·Deficit (-)

National Income 
 NI = Compensation for Employees + Proprietor's Income + Rental Income + Interest Income + Corporation Profit
 NI = GDP - Indirect business tax - Depreciation - Net foreign factor payment. 

Disposable Income
 DPI = NI - Household Income + Government Transfer Payment

Net Domestic Product
 GDP - Depreciation

Net National Product
 GNP - Depreciation

Gross National Product
 GDP - Net foreign factor payment.