You have a dual-status tax year when you have been both a resident alien and a nonresident alien in the same year. Dual status does not refer to your citizenship, only to your resident status in the United States. In determining your U.S. income tax liability for a dual-status tax year, different rules apply for the part of the year you are a resident of the United States and the part of the year you are a nonresident.

The most common dual-status tax years are the years of arrival and departure. See Dual-Status Aliens in chapter 1.

If you are married and choose to be treated as a U.S. resident for the entire year, as explained in chapter 1, the rules of this chapter do not apply to you for that year.

See chapter 12 for information about getting these publications and forms.

You must file your tax return on the basis of an annual accounting period called a tax year. If you have not previously established a fiscal tax year, your tax year is the calendar year. A calendar year is 12 consecutive months ending on December 31. If you have previously established a regular fiscal year (12 consecutive months ending on the last day of a month other than December, or a 52–53 week year) and are considered to be a U.S. resident for any calendar year, you will be treated as a U.S. resident for any part of your fiscal year that falls within that calendar year.