The 1040 is the main form you use to report your yearly income to the IRS

Form 1040 is the federal income tax return form that most U.S. taxpayers file each year. It tells the IRS how much money you earned, what deductions and credits you can claim, and how much tax you owe or should get back. The form itself is relatively short — usually one or two pages — but it works together with other schedules and forms that attach to it depending on your situation.

You file a 1040 if you are a U.S. citizen or resident alien with income from wages, self-employment, investments, or other sources. The IRS requires most people with income above a certain threshold to file, though some people file even if they earn less because they paid taxes through their paychecks and want a refund. The threshold changes each year and depends on your age, filing status, and type of income.

The 1040 is not the only form the IRS offers — there used to be a shorter version called the 1040-A and an even shorter one called the 1040-EZ — but as of the 2018 tax year, the IRS consolidated everything into one 1040 form. You still attach different schedules depending on what kind of income or deductions you have, which makes the overall package fit your specific situation.

Key Takeaways

  • Form 1040 is the standard federal income tax return that reports your total income, deductions, and tax liability for the year.
  • You file a 1040 if you earned income above the IRS threshold for your filing status, or if you want to claim a refund of taxes withheld from your paychecks.
  • The 1040 itself is short, but you attach schedules like Schedule C (self-employment), Schedule A (itemized deductions), or Schedule D (capital gains) depending on your income sources.
  • The IRS important date to file is usually April 15, though you can request an extension to October 15 by filing Form 4868.

What goes on the main 1040 form

The 1040 has sections for personal information, income, deductions, and tax calculation. At the top you enter your name, address, Social Security number, and filing status (single, married filing jointly, head of household, and so on). You also mark whether anyone can claim you as a dependent and whether you want to donate to the presidential election campaign fund.

The income section lists different types of earnings: wages from a W-2 job, interest and dividends, capital gains, self-employment income, and others. You add these up to get your total income. Then you subtract either the standard deduction (a flat amount set by the IRS each year) or itemized deductions (specific expenses you list on Schedule A). The result is your taxable income.

Below that, you calculate your tax using tax tables or the tax calculation worksheet, then you subtract any credits you may have access to for — the child tax credit, education credits, or others. You also account for taxes already paid through withholding on your paychecks or estimated tax payments you made during the year. The final number is either the tax you owe or the refund you should receive.

When you need to attach schedules to your 1040

Most people's income comes from a W-2 job, and their only deduction is the standard deduction. For them, the 1040 alone is enough. But if your situation is more complex, you attach schedules that provide detail on specific income or deductions.

Schedule C is for self-employment income — if you run a business, freelance, or have other income not reported on a W-2. You list your business income and expenses, and the form calculates your profit or loss. Schedule D is for capital gains and losses from selling stocks, real estate, or other investments. Schedule A is for itemized deductions like mortgage interest, property taxes, charitable donations, and medical expenses — you use this instead of the standard deduction if your total deductions are higher.

Other common schedules include Schedule 1 (for other income like alimony, rental income, or prizes), Schedule 2 (for additional taxes like self-employment tax), and Schedule 3 (for other credits and payments). You only file the schedules that explore to you. The IRS instructions for Form 1040 tell you which schedules you need based on your situation.

The difference between 1040 and other tax forms

The 1040 is for individual income tax. Other forms serve different purposes. Form 1040-SR is a version of the 1040 designed for people age 65 and older — it has larger print and is organized slightly differently, but it reports the same information. Form 1040-NR is for nonresident aliens who earned U.S. income.

If you own a business structured as a corporation, partnership, or S-corporation, you file a different form entirely — Form 1120 for a C-corporation, Form 1065 for a partnership, or Form 1120-S for an S-corporation. Those forms report the business's income and expenses, and then the business's owners report their share of the profit on their personal 1040.

Form 1040 is also different from the forms your employer and financial institutions send you. Your employer sends a W-2 showing wages and taxes withheld. Banks and brokerages send 1099 forms (1099-INT for interest, 1099-DIV for dividends, 1099-MISC for miscellaneous income, and others). These forms report income to both you and the IRS, and you use them to fill in your 1040.

How to get and file your 1040

You can read Form 1040 and its instructions free from IRS.gov. The IRS also publishes the forms on its website in PDF format, and you can print them and fill them out by hand. Many tax software programs — TurboTax, H&R Block, TaxAct, and others — guide you through the 1040 step by step and calculate everything for you. Some of these programs offer free versions if your income and situation are straightforward enough.

You can also work with a tax professional — a CPA, enrolled agent, or tax preparer — who will complete the 1040 for you. If you file electronically (which most people do), the IRS processes your return faster and you get a refund sooner. If you owe tax, you can pay online, by phone, or by mail when you file.

The important date to file is usually April 15 of the year after the tax year ends. So for the 2023 tax year, you file by April 15, 2024. If you cannot meet that important date, you can request an extension by filing Form 4868 before April 15. The extension gives you until October 15 to file, but it does not extend the important date to pay any tax you owe — you should pay by April 15 to avoid penalties and interest.

Common mistakes on the 1040

One frequent error is entering the wrong Social Security number or spelling your name differently than it appears on your Social Security card. The IRS matches your return to your account using this information, and mismatches can delay processing. Another mistake is forgetting to sign and date the form — an unsigned return is not valid and the IRS will reject it.

People also sometimes claim the wrong filing status or forget to report all their income. If you received a 1099 form, the IRS received a copy too, so unreported income will likely be caught. Claiming dependents you are not may have access to to claim, or claiming the same dependent twice (for example, if both parents file), is another common problem that triggers an audit or a correction notice.

Math errors are less common now because most people use tax software, which calculates automatically. But if you file by hand, double-check your arithmetic and make sure you transferred numbers correctly from your schedules to the main form. If you make a mistake after you file, you can file an amended return using Form 1040-X.

Frequently Asked Questions

Do I have to file a 1040 if I did not earn much money?

It depends on your income and filing status. The IRS sets a threshold each year — for 2023, a single person under 65 with only wage income had to file if they earned more than $13,850. But even if you earned less, you should file if you had taxes withheld from your paychecks, because you may be due a refund. You should also file if you are claiming a refund of taxes paid through estimated payments or if you may have access to for refundable credits like the Earned Income Tax Credit.

What if I have income from multiple sources?

List each type of income on the 1040 — wages on line 1a, interest on line 2a, dividends on line 5b, and so on. If you have self-employment income, you also complete Schedule C and attach it to your 1040. The form adds all your income together to calculate your total, then you subtract deductions and calculate your tax.

Can I file a 1040 if I am not a U.S. citizen?

If you are a resident alien (which has a specific IRS definition based on the substantial presence test or a green card), you file a regular 1040. If you are a nonresident alien, you file Form 1040-NR instead. Some nonresident aliens with U.S. income from wages or investments must file even if they do not have a Social Security number — they use an Individual Taxpayer Identification Number (ITIN) instead.

What happens if I file my 1040 late?

If you owe tax and file late, you face a failure-to-file penalty and interest on the unpaid amount. The penalty is usually 5 percent of the unpaid tax for each month you are late, up to 25 percent. If you are due a refund, there is no penalty for filing late, but you cannot claim a refund more than three years after the original important date.

Do I need to keep my 1040 after I file it?

Yes. Keep a copy of your filed 1040, all schedules, and supporting documents (W-2s, 1099s, receipts for deductions) for at least three years. The IRS can audit a return up to three years after you file, and sometimes longer if there is a substantial underreporting of income. Having your records makes it much easier to respond if the IRS has questions.