Main article: Gross income
The Internal Revenue Code states that "gross income means all income from whatever source derived," and gives specific examples.
Gross income is not limited to cash received. "It includes income realized in any form, whether money, property, or services." Gross income includes wages and tips, fees for performing services, gain from sale of inventory or other property, interest, dividends, rents, royalties, pensions, alimony, and many other types of income. Items must be included in income when received or accrued. The amount included is the amount the taxpayer is entitled to receive. Gains on property are the gross proceeds less amounts returned, cost of goods sold, or tax basis of property sold.
Certain types of income are exempt from income tax. Among the more common types of exempt income are interest on municipal bonds, a portion of Social Security benefits, life insurance proceeds, gifts or inheritances, and the value of many employee benefits.