USAFacts categorizes government budget data to allocate spending appropriately and to arrive at the estimate presented here. All spending occurs at the federal level. Foreign affairs spending includes aid and assistance for development, humanitarian, or security purposes; exchange of information; international financial programs; and conduct of foreign affairs.

Government revenue and expenditures are based on data from the Office of Management and Budget, the Census Bureau, and the Bureau of Economic Analysis. Each is published annually, although due to collection times, state and local government data are not as current as federal data. Thus, when combining federal, state, and local revenues and expenditures, the most recent year for a combined number may be delayed.

Foreign assistance usually accounts for 1% or less of federal spending.

Foreign assistance, or aid, is a foreign policy tool used by the federal government to provide resources to actors in other countries, including governments or private entities. Types of foreign assistance include specific projects, services, goods, or cash. Assistance is primarily handled by the US Agency for International Development (USAID), though 21 agencies and departments are involved in funding and managing aid.

USAID publishes data tracking each instance of foreign assistance. Each activity is classified into one of two broad objectives — economic and military — and in more specific categories such as humanitarian assistance, environment, or peace and security. The data can be used to interpret the US government’s foreign policy each year.

According to USAID, there can be up to a two-year lag before a year’s data would be considered complete. Data updates are made regularly.