The legal definition and the economical definition of taxes differ in that economists do not regard many transfers to governments as taxes. For example, some transfers to the public sector are comparable to prices. Examples include tuition at public universities and fees for utilities provided by local governments. Governments also obtain resources by "creating" money and coins (for example, by printing bills and by minting coins), through voluntary gifts (for example, contributions to public universities and museums), by imposing penalties (such as traffic fines), by borrowing, and by confiscating wealth. From the view of economists, a tax is a non-penal, yet compulsory transfer of resources from the private to the public sector levied on a basis of predetermined criteria and without reference to specific benefit received.
In modern taxation systems, governments levy taxes in money; but in-kind and corvée taxation are characteristic of traditional or pre-capitalist states and their functional equivalents. The method of taxation and the government expenditure of taxes raised is often highly debated in politics and economics. Tax collection is performed by a government agency such as the Canada Revenue Agency, the Internal Revenue Service (IRS) in the United States, Her Majesty's Revenue and Customs (HMRC) in the United Kingdom or Federal Tax Service in Russia. When taxes are not fully paid, the state may impose civil penalties (such as fines or forfeiture) or criminal penalties (such as incarceration) on the non-paying entity or individual.
The levying of taxes aims to raise revenue to fund governing and/or to alter prices in order to affect demand. States and their functional equivalents throughout history have used money provided by taxation to carry out many functions. Some of these include expenditures on economic infrastructure (roads, public transportation, sanitation, legal systems, public safety, education, health-care systems), military, scientific research, culture and the arts, public works, distribution, data collection and dissemination, public insurance, and the operation of government itself. A government's ability to raise taxes is called its fiscal capacity.
When expenditures exceed tax revenue, a government accumulates debt. A portion of taxes may be used to service past debts. Governments also use taxes to fund welfare and public services. These services can include education systems, pensions for the elderly, unemployment benefits, and public transportation. Energy, water and waste management systems are also common public utilities.
According to the proponents of the chartalist theory of money creation, taxes are not needed for government revenue, as long as the government in question is able to issue fiat money. According to this view, the purpose of taxation is to maintain the stability of the currency, express public policy regarding the distribution of wealth, subsidizing certain industries or population groups or isolating the costs of certain benefits, such as highways or social security.