The 1040 is your main federal income tax return

The Form 1040 is the document you file with the IRS each year to report your income, claim deductions, and calculate how much federal income tax you owe or how much you should get back. It is the primary form used by individual taxpayers in the United States. Almost every person who earns income and is required to file taxes will use a 1040 or one of its variants.

The IRS sends you a refund if you paid too much tax during the year through withholding or estimated payments. You owe additional tax if you paid too little. The 1040 is where all of that gets settled.

Key Takeaways

  • The 1040 reports your income from all sources — wages, self-employment, investments, retirement accounts — and calculates your tax liability for the year.
  • You file the 1040 by April 15 of the following year, unless you request an extension, which gives you until October 15.
  • The form itself is relatively short, but you will attach supporting schedules if you have self-employment income, itemized deductions, capital gains, or other complex items.
  • The IRS uses your 1040 to verify that the income reported by your employer, bank, and investment firms matches what you reported.
  • Filing a 1040 is required if your income exceeds the standard deduction for your age and filing status, even if you expect a refund.

What income you report on the 1040

The 1040 asks you to list income from every source. This includes wages from an employer (reported on a W-2), self-employment income, interest and dividends, capital gains from selling investments, retirement account distributions, rental income, and other sources. You do not report every dollar you receive — some income is tax-exempt — but the form walks you through which types count.

If you have a W-2 from an employer, you enter the wages shown on that form. If you are self-employed, you calculate your net profit on Schedule C and bring that number to the 1040. Investment income appears on Schedule B or Schedule D depending on the type. The 1040 itself has space for the most common income types, and you attach schedules for anything more detailed.

Deductions and credits that lower your tax

After you report income, the 1040 lets you reduce your taxable income through deductions. You can take the standard deduction — a flat amount set by the IRS each year that depends on your age and filing status — or you can itemize deductions if you have enough may have access to expenses like mortgage interest, state and local taxes, or charitable donations. You choose whichever gives you the larger deduction.

The 1040 also accounts for tax credits, which are different from deductions because they reduce your tax dollar-for-dollar rather than reducing your income. Common credits include the Earned Income Tax Credit, the Child Tax Credit, and education credits. Credits are often more valuable than deductions, so the form asks about them separately.

How the 1040 connects to documents from your employer and banks

Your employer sends you a W-2 showing wages and taxes withheld. Your bank or investment firm sends you a 1099 form showing interest, dividends, or other income. The IRS receives copies of all these forms too. When you file your 1040, the IRS compares what you reported against what your employer and financial institutions reported. If the numbers do not match, the IRS will contact you to explain the difference.

This is why it is important to report all income on your 1040, even if you think the IRS will not notice. The matching process is automated, and discrepancies trigger notices. You will need the W-2s and 1099s in front of you when you fill out the 1040.

The 1040-SR for taxpayers age 65 and older

The IRS offers a version called the 1040-SR designed for people age 65 or older. It is laid out slightly differently to make it easier to read and includes a larger standard deduction amount built into the form. You are not required to use the 1040-SR — you can file the regular 1040 at any age — but many older taxpayers find it simpler.

The 1040-SR asks the same questions and produces the same result as the regular 1040. The choice between them is about readability and convenience, not tax outcome.

Filing important date and extensions

The 1040 is due on April 15 of the year following the tax year you are reporting. If April 15 falls on a weekend or holiday, the important date moves to the next business day. You can request an automatic extension by filing Form 4868, which gives you until October 15 to file. An extension delays when you file, but it does not delay when your taxes are due — if you owe money, interest and penalties start accruing on April 15 even if you have not filed yet.

Many people file early to get a refund sooner. There is no penalty for filing before the important date, and the IRS processes returns faster in January and February than in April.

Where to file and what happens after

You can file the 1040 electronically through tax software, through a tax professional, or by mailing a paper copy to the IRS address shown in the instructions. Electronic filing is faster and more accurate because the software catches common errors before you submit. The IRS processes e-filed returns in about 21 days if there are no issues.

After you file, the IRS reviews your return. If everything matches the information they received from employers and financial institutions, you will receive your refund or a bill for additional tax within a few weeks. If there is a discrepancy, the IRS will send you a notice asking for clarification or additional documentation.

Frequently Asked Questions

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

You must file if your income exceeds the standard deduction for your age and filing status. For 2024, the standard deduction is $14,600 for a single person under 65. If you earned less than that, you are not required to file, but you may want to file anyway to claim a refund of taxes withheld or to claim the Earned Income Tax Credit.

What is the difference between the 1040 and a 1040-EZ?

The IRS discontinued the 1040-EZ after 2017. All taxpayers now file either the 1040 or the 1040-SR. The regular 1040 works for any income level and any filing situation, so there is no longer a separate simplified version.

Can I file the 1040 myself, or do I need a tax professional?

You can file the 1040 yourself using tax software, which guides you through each question and calculates your tax automatically. Many people with straightforward situations — W-2 income, standard deduction, no investments — find this approach straightforward. If you have self-employment income, rental property, or complex deductions, a tax professional can help you avoid mistakes and find deductions you might miss.

What happens if I make a mistake on my 1040?

If you discover an error after filing, you can file an amended return using Form 1040-X. The IRS also catches many errors during processing and will contact you if they find a problem. You have three years to file an amended return to claim a refund, but the IRS can audit you for up to three years from the filing date.

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

Yes. Keep a copy of your filed 1040 and all supporting documents for at least three years. If the IRS audits you, you will need to show the documents that back up the numbers on your return. Many people keep tax records for seven years as a precaution.