Form 1040

Form 1040 (officially, the "U.S. Individual Income Tax Return") is one of three IRS tax forms (see variants section for explanations of each) used for personal (individual) federal income tax returns filed with the Internal Revenue Service (IRS) by United States residents for tax purposes.

Income tax returns for individual calendar year taxpayers are due by Tax Day, which is usually April 15 of the next year, except when April 15 falls on a Saturday, Sunday, or a legal holiday. In those circumstances, the returns are due on the next business day. An automatic extension until October 15 to file Form 1040 can be obtained by filing Form 4868.

Form 1040 consists of two full pages (79 lines in total) not counting attachments. The first page collects information about the taxpayer(s), dependents, income items, and adjustments to income. In particular, the taxpayer specifies his/her filing status and personal exemptions on this page. The second page calculates the allowable deductions and credits, tax due given the income figure, and applies funds already withheld from wages or estimated payments made towards the tax liability. At the top of the first page is the presidential election campaign fund checkoff, which allows individuals to designate that the federal government give $3 of the tax it receives to the Presidential election campaign fund. The instructions booklet for Form 1040 is 104 pages as of 2014.

Altogether, over 147 million returns were filed for Form 1040 and its variants in the year 2014, 80% of which were filed electronically.

Form 1040 (or a variant thereof) is the main tax form filed by individuals who are deemed residents of the United States for tax purposes. The corresponding main form filed by businesses is Form 1120, also called the U.S. Corporation Income Tax Return.

An individual is considered a resident of the United States for tax purposes if he or she is a citizen of the United States or a resident alien of the United States for tax purposes. An individual is a resident alien of the United States if he or she passes either the Substantial Presence Test or the Green Card Test, although there are also some other cases; individuals who have taxable income in the United States but fail the criteria for being resident aliens must file as nonresident aliens for tax purposes. While residents of the United States for tax purposes file Forms 1040, 1040A, or 1040EZ, nonresident aliens must file Form 1040NR or 1040NR-EZ. There is also a "dual status alien" for aliens whose status changed during the year.

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