The 1040 is the main form you use to report your income and calculate what you owe in federal income tax

The Form 1040 is the document the Internal Revenue Service (IRS) uses to collect information about your income, deductions, and tax credits for the year. You file it once per year to tell the IRS how much money you earned, what you can subtract from that income, and whether you owe additional tax or will receive a refund. Almost every person who earns income in the United States files a 1040 or one of its variations.

The form itself is a few pages long and asks for basic information: your name, address, Social Security number, filing status (single, married, head of household, and so on), and then sections where you report different types of income. Below that are lines for deductions and credits that reduce what you owe. At the bottom, the form calculates your total tax liability and compares it to what you already paid through payroll withholding or estimated tax payments during the year.

You file the 1040 by the federal tax important date, which is usually April 15 of the year after the tax year ends. You can file by mail, through tax software, or with the help of a tax preparer. The IRS processes your return and either sends you a refund or bills you for additional tax owed.

Key Takeaways

  • The 1040 reports your total income for the year and calculates your federal income tax liability based on your filing status and income level.
  • You use the 1040 to claim deductions and credits that reduce the amount of tax you owe, such as the standard deduction or child tax credits.
  • The form compares your total tax liability to what you already paid through employer withholding or estimated payments to determine if you owe money or receive a refund.
  • The IRS offers three versions of the 1040: the standard 1040, the 1040-SR for people 65 and older, and the 1040-NR for nonresidents.
  • You must file by April 15 unless you request an extension, and you can file by mail, through software, or with a tax professional.

Who has to file a 1040

You must file a 1040 if your income exceeds a certain threshold that depends on your age, filing status, and type of income. For the 2023 tax year, a single person under 65 must file if their gross income was $13,850 or more. A married couple filing jointly must file if their combined income was $27,700 or more. These thresholds change each year and are higher for people 65 and older.

Even if your income is below the threshold, you should file if you had taxes withheld from your paychecks or made estimated tax payments during the year. Filing allows you to claim a refund of that money. You must also file if you owe self-employment tax (Social Security and Medicare tax on income from self-employment) or if you received income that required withholding but no tax was taken out.

Some people file even when not required because they want to claim refundable tax credits, such as the Earned Income Tax Credit (EITC) or the Additional Child Tax Credit. These credits can result in a refund even if you owe no tax.

The three versions of the 1040 and which one you use

The IRS publishes three versions of the 1040, and which one you file depends on your residency status and age. The standard Form 1040 is for U.S. citizens and residents of any age. The Form 1040-SR is designed for people 65 and older and has larger print and a simpler layout, though it covers the same income and deductions as the standard form. The Form 1040-NR is for nonresident aliens — people who are not U.S. citizens and do not meet the residency test for tax purposes.

Most people file the standard 1040. You use the 1040-SR only if you are 65 or older by December 31 of the tax year; using it is optional, not required. You use the 1040-NR only if you are a nonresident alien and earned income in the United States. If you are unsure which form applies to you, the IRS website has a worksheet to help you determine your residency status.

What income you report on the 1040

The 1040 asks you to report all income you received during the tax year. This includes wages and salaries from your employer (which appear on your W-2 form), interest and dividends from investments, capital gains from selling stocks or property, rental income, self-employment income, and income from retirement accounts. You also report income from Social Security, pensions, annuities, and unemployment benefits.

Some types of income are taxable; others are not. For example, wages are fully taxable, but a portion of Social Security benefits may be taxable depending on your total income. Interest from municipal bonds is usually not taxable. The 1040 has separate lines for different income types so the IRS can track what you earned and verify it against information they receive from employers, banks, and other payers.

If you receive income that is not reported to the IRS on a form like a W-2 or 1099, you still must report it on your 1040. This includes cash tips, barter income, and prizes. Failing to report income can result in penalties and interest.

Deductions and credits you can claim on the 1040

The 1040 has sections where you claim deductions and credits that reduce your tax liability. A deduction reduces your taxable income, while a credit reduces your tax bill dollar-for-dollar. Most people claim the standard deduction, which is a fixed amount based on your filing status and age. For 2023, the standard deduction was $13,850 for a single filer under 65 and $27,700 for a married couple filing jointly.

If you have large expenses like mortgage interest, property taxes, or charitable donations, you may benefit from itemizing deductions instead of taking the standard deduction. To itemize, you file Schedule A along with your 1040 and list each deduction separately. Most people find the standard deduction is larger and use that instead.

Common credits include the Child Tax Credit (up to $2,000 per child), the Earned Income Tax Credit (for lower-income workers), the American Opportunity Credit (for education expenses), and the Saver's Credit (for retirement contributions). Credits are more valuable than deductions because they reduce your tax directly. You claim credits on the 1040 or on schedules that attach to it.

How the 1040 calculates what you owe or your refund

The 1040 follows a step-by-step calculation. First, you add up all your income from all sources. Then you subtract either the standard deduction or your itemized deductions to arrive at your taxable income. Next, you use the tax tables or tax rate schedules provided by the IRS to find your total tax liability based on your taxable income and filing status.

After you know your total tax liability, you subtract any credits you are may have access to to claim. This gives you your net tax liability — the amount you actually owe. Then the form compares this to the total amount of tax that was already withheld from your paychecks or paid through estimated tax payments during the year. If you paid more than you owe, you receive a refund. If you paid less, you owe the difference.

The 1040 also includes lines for other taxes you may owe, such as self-employment tax if you are self-employed, or the net investment income tax if your income exceeds certain thresholds. These are added to your income tax to calculate your total tax liability.

Schedules and forms that attach to the 1040

The 1040 by itself covers basic income and deductions, but most people need to attach additional forms and schedules that provide more detail. Schedule A is used if you itemize deductions instead of taking the standard deduction. Schedule B reports interest and dividend income. Schedule C reports self-employment income and expenses. Schedule D reports capital gains and losses from selling investments or property.

Other common schedules include Schedule E (for rental income), Schedule 1 (for additional income and adjustments), and Schedule 2 (for additional taxes). If you have dependents, you also file Schedule 8812 to claim the Child Tax Credit. If you made contributions to a traditional IRA, you may file Form 8606 to report nondeductible contributions.

Tax software and tax preparers handle attaching the correct schedules automatically based on the information you provide. If you file by mail, you must include all necessary schedules or the IRS will reject your return or request more information.

Frequently Asked Questions

Can I file a 1040 if I am self-employed?

Yes. Self-employed people file the same 1040 as everyone else, but they also attach Schedule C to report their business income and expenses. On Schedule C, you calculate your net profit or loss. You also file Schedule SE to calculate self-employment tax (Social Security and Medicare tax), which is added to your income tax liability on the 1040.

What happens if I file my 1040 late?

If you file after April 15 without requesting an extension, you may owe a failure-to-file penalty and interest on any tax you owe. The penalty is usually 5% of your unpaid tax for each month your return is late. If you need more time, you can request an automatic six-month extension by filing Form 4868 before the important date. An extension gives you until October 15 to file, but you still owe any tax due by April 15.

Do I need to file a 1040 if I only have Social Security income?

Not necessarily. If Social Security is your only income, you generally do not have to file unless your income exceeds the threshold for your filing status. However, if you have other income or had taxes withheld, you may want to file to claim a refund. Use the IRS worksheet on their website to determine whether you must file.

Can I amend my 1040 after I file it?

Yes. If you made a mistake or forgot to report income or claim a deduction, you can file an amended return using Form 1040-X. You must file the amended return within three years of the original filing date to claim a refund, though you can file it later if you owe additional tax. The IRS will process your amended return and send you a revised notice of what you owe or your refund amount.

What if I cannot pay the tax I owe on my 1040?

If you owe tax but cannot pay it in full by the important date, you can still file your return on time to avoid the failure-to-file penalty. You will owe interest and a failure-to-pay penalty on the unpaid balance, but these are smaller than the failure-to-file penalty. The IRS also offers payment plans and other options; you can contact them or use their website to set up a plan.