A fiscal year (or financial year, or sometimes budget year) is used in government accounting, which varies between countries, and for budget purposes. It is also used for financial reporting by businesses and other organizations. Laws in many jurisdictions require company financial reports to be prepared and published on an annual basis but generally with the reporting period not aligning with the calendar year (1 January to 31 December). Taxation laws generally require accounting records to be maintained and taxes calculated on an annual basis, which usually corresponds to the fiscal year used for government purposes. The calculation of tax on an annual basis is especially relevant for direct taxes, such as income tax. Many annual government fees—such as council tax and license fees, are also levied on a fiscal year basis, but others are charged on an anniversary basis.

Some companies, such as Cisco Systems, end their fiscal year on the same day of the week each year: the day that is closest to a particular date (for example, the Friday closest to 31 December). Under such a system, some fiscal years have 52 weeks and others 53 weeks.

The calendar year is used as the fiscal year by about 65% of publicly-traded companies in the United States and for most large corporations in the United Kingdom. That is the case in many countries around the world with a few exceptions such as Australia, New Zealand, and Japan.

Many universities have a fiscal year which ends during the summer to align the fiscal year with the academic year (and, in some cases involving public universities, with the state government's fiscal year) and also because the university is normally less busy during the summer months. In the Northern Hemisphere, that is July to the next June. In the Southern Hemisphere, that is the calendar year, January to December. In a similar fashion, many nonprofit performing arts organizations will have a fiscal year which ends during the summer, so that their performance season that begins in the fall and ends in the spring will be within one fiscal year.

Some media/communication-based organizations use a broadcast calendar as the basis for their fiscal year.