Form 1040, officially titled the U.S. Individual Income Tax Return, is an IRS tax form used by United States residents to file personal federal income tax returns. The form is used to calculate a taxpayer's total taxable income and to determine the amount of tax owed to or refundable from the federal government.
For individual taxpayers who follow the calendar year, income tax returns are generally due by Tax Day, which typically falls on April 15 of the following year. If April 15 falls on a Saturday, Sunday, or legal holiday, the due date is extended to the next business day. Taxpayers may obtain an automatic extension to file Form 1040 until October 15 by submitting Form 4868. However, this extension applies only to the filing deadline; any taxes owed must still be paid by the original due date to avoid penalties and interest.
Form 1040 consists of two pages (23 lines in total), not counting attachments. The first page collects information about the taxpayer(s) and dependents. In particular, the taxpayer's filing status is reported on this page. The second page reports income, calculates the allowable deductions and credits, figures the tax due given adjusted income, and applies funds already withheld from wages or estimated payments made towards tax liability. On the right side 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. Altogether, 142 million individual income tax returns were filed for the tax year 2018 (filing season 2019), 92% of which were filed electronically.
Filing requirements
Who must file?
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 Form 1040, nonresident aliens must file Form 1040NR or 1040NR-EZ. There is also a "dual status alien" for aliens whose status changed during the year.
Resident aliens of the United States for tax purposes must generally file if their income crosses a threshold where their taxable income is likely to be positive, but there are many other cases where it may be legally desirable to file. For instance, even if not required, individuals can file a return in order to receive a refund on withheld income or to receive certain credits (e.g. earned income tax credit).
Filing modalities
The form may be filed either by paper or online.
Paper filing
Paper filing is the universally accepted filing method. Form 1040, along with its variants, schedules, and instructions, can be downloaded as PDFs from the Internal Revenue Service website. Finalized versions of the forms for the tax year (which in the US is the same as the calendar year) are released near the end of January of the following year.
Paper forms can be filled and saved electronically using a compatible PDF reader, and then printed. This way, it is easy to keep electronic copies of one's filled forms despite filing by paper. Alternatively, they can be printed out and filled by hand. A combination of the approaches may also be used, with some content filled in electronically and additional content written in by hand. As a general rule, where possible, it makes sense to fill electronically, but in some cases filling by hand may be necessary (for instance, if additional notes of explanation need to be added, or the font used for electronic filling is too large to fit the information in the space provided).
The only parts of the form that cannot be filled electronically are the signature lines.
The paper Form 1040, along with all relevant schedules and additional forms, must be sent in a single packet by mail or courier to an IRS address determined by the US state the taxpayer is filing from and whether or not a payment is enclosed.
The IRS accepts returns that are stapled or paperclipped together. However, any check or payment voucher, as well as accompanying Form 1040-V, must not be stapled or paperclipped with the rest of the return, since payments are processed separately.
Electronic filing
The IRS allows US residents for tax purposes to file electronically in three ways:
Those with incomes of $66,000 or less may file electronically using IRS Free File, a free e-filing tool (there are some other conditions necessary to be eligible for free filing; in particular, some kinds of income and deductions cannot be handled by free filing). It is possible to prepare one's tax return using a tax compliance software approved by the IRS and have the software file the return electronically. One can use a tax professional who has been accepted by the IRS for electronic filing.
Many paid tax preparers are required to file individual tax returns electronically, and most tax compliance software file electronically on the taxpayer's behalf. Even the tax preparers who are not so required, must file Form 8948 if they choose paper filing, providing an explanation for why they are not filing electronically.
Comparison
If one is not eligible for IRS Free File, depending on the company used it might cost hundreds of dollars to file electronically, whereas paper filing has no costs beyond those of printing and mailing. Furthermore, the available existing electronic filing options may not offer sufficient flexibility with respect to arranging one's tax return, adding attachments, or putting written notes of explanation that can help preempt IRS questions. In the past, filing electronically may have exposed the taxpayer's data to the risk of accidental loss or identity theft, but now e-filing with reputable companies is considered more secure than paper filing.
Signature requirement
Form 1040 must be signed and dated in order to be considered valid. If filing jointly with a spouse, both must sign and date. If a return is submitted electronically, individuals must use either a Self-Select PIN or Practitioner PIN.
Substitute return
If an individual decides not to file a return, the IRS may (after it has sent several reminders) file a substitute return.
Variants
For filing the regular tax return, in addition to the standard Form 1040, there are currently three variants: the 1040-NR, 1040-SR, and 1040-X.
Form 1040-NR is used by taxpayers who are considered "non-resident aliens" for tax purposes.
Form 1040-SR may be used by taxpayers who are 65 or older. The 1040-SR variant is functionally the same as Form 1040, but is easier to fill out by hand because the text and checkboxes are larger. Seniors may continue to use the standard 1040 for tax filing if they prefer. Its creation was mandated by the Bipartisan Budget Act of 2018, and it was first used for filing taxes for the 2019 tax year.
Form 1040-X (officially, the "Amended U.S. Individual Tax Return") is used to make corrections on Form 1040, Form 1040A, and Form 1040EZ tax returns that have been previously filed (note: forms 1040-A and 1040-EZ were discontinued starting with tax year 2018, but a 1040X may still be filed amending one of these tax forms filed for previous years).
Accompanying payments
Form 1040-V
The 1040-V (officially, the "Payment Voucher for Form 1040") is used as an optional payment voucher to be sent in along with a payment for any balance due on the "Amount you owe" line of the 1040.
The form is entirely optional. The IRS will accept payment without the 1040V form. However including the 1040-V allows the IRS to process payments more efficiently.
Form 1040-V and any accompanying payment should be included in the same packet as the tax return, but should not be stapled or paper-clipped along with the tax return, since it is processed separately.
Schedules and extra forms
Since 1961 Form 1040 has had various separate attachments to the form. These attachments are usually called "schedules" because prior to the 1961, the related sections were schedules on the main form identified by letter. Form 1040 currently has 20 attachments, which may need to be filed depending on the taxpayer. For 2009 and 2010 there was an additional form, , due to the "Making Work Pay" provision of the American Recovery and Reinvestment Act of 2009 ("the stimulus").
Starting in 2018, 1040 was "simplified" by separating out 6 new schedules numbers Schedule 1 through Schedule 6 to make parts of the main form optional. The new schedules had the prior old 1040 line numbers to make transition easier.
In addition to the listed schedules, there are dozens of other forms that may be required when filing a personal income tax return. Typically these will provide additional details for deductions taken or income earned that are listed either on form 1040 or its subsequent schedules.