Gross income in United States tax law is receipts and gains from all sources. Gross income is the starting point for determining Federal and state income tax of individuals, corporations, estates and trusts, whether resident or nonresident."Except as otherwise provided" by law, Gross income means "all income from whatever source," and is not limited to cash received. However, tax regulations expand on this and say "all income from whatever source derived, unless excluded by law." The amount of income recognized is generally the value received or which the taxpayer has a right to receive. Certain types of income are specifically excluded from gross income.The time at which gross income becomes taxable is determined under Federal tax rules, which differ in some cases from financial accounting rules.