The 1040 is your main federal income tax return

The Form 1040 is the document you send to the IRS to report your income for the year and calculate how much federal income tax you owe — or how much the government owes you. It is the central form for almost every U.S. taxpayer. Whether you are self-employed, work for a company, receive investment income, or have a combination of income sources, the 1040 is where you tie it all together and settle your tax account with the federal government.

The 1040 itself is relatively short — usually two pages — but it pulls information from other forms and schedules you file alongside it. Those supporting documents report the details (your W-2 from your employer, your 1099s from side income, your charitable donations), while the 1040 summarizes everything and does the math that determines your final tax bill or refund.

You file the 1040 once per year, by April 15 of the year following the tax year. For example, you file your 2024 1040 by April 15, 2025. The IRS uses it to verify that you reported all your income, that you claimed only the deductions and credits you are may have access to to, and that you paid the right amount of tax.

Key Takeaways

  • The 1040 summarizes all your income sources and calculates your federal income tax for the year.
  • Almost every U.S. taxpayer files a 1040, whether they work for an employer, are self-employed, or have investment income.
  • The 1040 pulls information from supporting forms like W-2s, 1099s, and schedules for deductions and credits.
  • You file the 1040 by April 15 of the year after the tax year ends, and it determines whether you owe tax or receive a refund.
  • The form has changed over time, but the current version works the same way for most taxpayers regardless of income level.

What information goes on the 1040

The 1040 starts with your personal information: your name, address, Social Security number, and filing status (single, married filing jointly, head of household, and so on). Your filing status matters because it determines your tax brackets and standard deduction.

The main body of the form lists your income. Line 1 is wages from your W-2. Lines 2 through 5 are for interest, dividends, capital gains, and other investment income. Line 6 is for business income if you are self-employed. You add these up to get your total income. Then you subtract either the standard deduction or your itemized deductions (whichever is larger) to arrive at your taxable income. The tax tables or tax software then calculate the federal income tax on that amount.

Below that, you report any tax credits you are may have access to to — the Earned Income Tax Credit, child tax credits, education credits, and others. Credits reduce your tax dollar-for-dollar, so they are more valuable than deductions. Finally, you compare the tax you owe to the tax that was already withheld from your paychecks or paid through estimated tax payments during the year. If you overpaid, you get a refund. If you underpaid, you owe the difference.

Who must file a 1040

You must file a 1040 if your income exceeds a threshold set by the IRS each year. The threshold depends on your age, filing status, and type of income. For 2024, a single person under 65 must file if their income is $14,600 or more. A married couple filing jointly must file if their combined income is $29,200 or more. These numbers change each year, and they are higher if you are 65 or 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. Filing allows you to claim a refund of that overpayment. You should also file if you are may have access to to refundable credits like the Earned Income Tax Credit, because those credits can result in a refund even if you owe no tax.

Self-employed people must file if their net business income is $400 or more, regardless of their total income. This is because self-employment tax (Social Security and Medicare tax) is owed on that income, and the 1040 is where you report and pay it.

How the 1040 connects to other tax forms

The 1040 does not stand alone. Your employer sends you a W-2 if you work for a company, and you report the wages from that W-2 on your 1040. If you have side income — freelance work, rental income, investment sales — you receive a 1099 form (the exact type depends on the income source), and you report that on your 1040 or on a supporting schedule.

If you itemize deductions instead of taking the standard deduction, you file Schedule A alongside your 1040 to list mortgage interest, property taxes, charitable donations, and other deductible expenses. If you are self-employed, you file Schedule C to report your business income and expenses, and the net profit from Schedule C goes on your 1040. If you have capital gains or losses, you file Schedule D. These schedules do the detailed work; the 1040 collects the results and calculates your tax.

Tax software walks you through these forms in order and fills in your 1040 automatically based on your answers. If you file by hand, you complete each schedule first, then transfer the totals to the appropriate lines on the 1040.

The difference between the 1040 and other return forms

The IRS offers a few versions of the individual income tax return. The 1040-SR is designed for people 65 and older and has larger print and a slightly different layout, but it serves the same purpose as the 1040. Some taxpayers with very straightforward returns — only wages and no dependents — used to be able to file a 1040-EZ, but that form was discontinued after 2018. Now almost everyone files the standard 1040.

The 1040 is different from business tax returns like the 1120 (for corporations) or 1065 (for partnerships). Those forms are filed by the business itself. If you own a business, the business may file its own return, and then you report your share of the business income on your personal 1040.

The 1040 is also different from state income tax returns. Most states have their own income tax and their own return form. You file both your federal 1040 and your state return, usually at the same time. A few states have no income tax, so residents of those states file only the 1040.

What happens after you file your 1040

Once you file your 1040, the IRS processes it. If you are owed a refund, the IRS mails it to you or deposits it directly to your bank account if you provided banking information. Refunds typically arrive within 21 days of the IRS receiving your return, though it can take longer if there are errors or if the IRS needs to verify information.

If you owe tax, you must pay by April 15. If you cannot pay in full, you can set up a payment plan with the IRS. The IRS charges interest and penalties on unpaid tax, so paying as soon as you can is important.

The IRS keeps your 1040 on file and uses it to verify your income, check that you reported all your income sources, and confirm that you paid the correct amount of tax. If the IRS finds a discrepancy — for example, if a 1099 you received shows more income than you reported — it may contact you to ask for an explanation or to pay additional tax plus interest and penalties.

Common mistakes on the 1040

The most common mistake is mismatching your name or Social Security number on the 1040 with the name and number on your W-2s and 1099s. The IRS matches these documents electronically, and even a small difference can delay processing or trigger an audit notice. Always double-check that your name and number are spelled and formatted the same way on every document.

Another frequent error is forgetting to report all income. If you have a side job, rental income, or investment income, you must report it even if you did not receive a 1099 for it. The IRS receives copies of 1099s sent to you, so if you leave income off your 1040, the IRS will likely catch it.

Claiming deductions or credits you are not may have access to to is also common. For example, you cannot claim a dependent if that person does not meet the IRS definition of a dependent, and you cannot claim the Earned Income Tax Credit if your income is too high. Tax software usually prevents these mistakes by asking screening questions, but if you file by hand or use outdated information, you may make an error.

Frequently Asked Questions

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

You must file if your income exceeds the IRS threshold for your filing status and age. For 2024, that is $14,600 for a single person under 65. However, you should file even if you are below the threshold if you had taxes withheld from your paychecks, because you may be owed a refund. You should also file if you are may have access to to the Earned Income Tax Credit.

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

Yes. Self-employed people file the same 1040 as everyone else, but they also file Schedule C to report their business income and expenses. You must file if your net business income is $400 or more, even if your total income is below the standard filing threshold, because you owe self-employment tax on that income.

What if I made a mistake on my 1040 after I filed it?

You can file an amended return using Form 1040-X. You have three years from the original due date to file an amended return and claim a refund, or seven years if you are reporting income you forgot to include. If you owe additional tax, file the amended return as soon as you discover the error to minimize interest and penalties.

Do I need to file a 1040 if I live in a state with no income tax?

You still file a federal 1040 to the IRS, because the federal government collects income tax regardless of where you live. States with no income tax straightforward do not require a state return. You file only the 1040 to the IRS, not to your state.

What is the difference between the 1040 and the 1040-SR?

The 1040-SR is designed for taxpayers 65 and older and has larger print and a slightly different layout for readability. It serves the same purpose as the 1040 and reports income and tax the same way. You can file either form if you are 65 or older; the choice is yours.