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

The 1040 is the federal income tax return form. You file it once a year to tell the Internal Revenue Service (IRS) how much money you earned, what deductions and credits you can claim, and how much tax you owe or should get back. The IRS uses your 1040 to calculate whether you paid enough tax throughout the year.

The form itself is relatively short — usually one or two pages — but it pulls information from other documents and forms you may have received from employers, banks, and investment accounts. Most people file their 1040 between January and April 15, though you can file earlier if you have all your documents ready.

You must file a 1040 if your income is above a certain threshold. That threshold depends on your age, filing status (single, married, head of household), and whether you are claimed as a dependent. The IRS publishes the current thresholds each year, and they change slightly to account for inflation.

Key Takeaways

  • The 1040 reports your total income for the year and calculates whether you owe federal income tax or will receive a refund.
  • You must file if your income exceeds the IRS threshold for your filing status and age, which changes each tax year.
  • The form requires information from documents like W-2s from employers, 1099s from other income sources, and receipts for deductions.
  • You can file on paper by mail or electronically through tax software or a tax preparer, and electronic filing is faster and more accurate.
  • If you do not file when required, you may face penalties and interest, and you will not receive any refund you are owed.

What information goes on your 1040

Your 1040 starts with personal information: your name, address, Social Security number, and filing status. Then you report all sources of income. This includes wages from a job (reported on a W-2 form your employer sends you), self-employment income, interest and dividends from savings and investments, rental income, and any other money you received.

After you list your income, you report deductions. A deduction reduces the amount of income that is subject to tax. You can either take the standard deduction — a flat amount set by the IRS each year that depends on your filing status — or itemize deductions by listing specific expenses like mortgage interest, state and local taxes, or charitable donations. Most people take the standard deduction because it is simpler and often larger than their itemized deductions would be.

Next, you claim any tax credits you are owed. A tax credit is different from a deduction: it reduces the actual tax you owe, dollar for dollar. Common credits include the Earned Income Tax Credit (EITC) for lower-income workers, the Child Tax Credit, and education credits. The 1040 guides you to other forms if you claim certain credits.

Finally, the form calculates your total tax liability and compares it to the amount you already paid through payroll withholding or estimated tax payments. If you paid too much, you get a refund. If you paid too little, you owe the difference.

Documents you need before you file

Gather these documents before you start your 1040. If you worked for an employer, you will receive a W-2 form by January 31 showing your wages and taxes withheld. If you received income from sources other than an employer — such as freelance work, rental income, or investment income — you will receive a 1099 form. The type of 1099 depends on the income source: 1099-NEC for self-employment, 1099-INT for interest, 1099-DIV for dividends, and so on.

If you own a home, you will need documentation of mortgage interest and property taxes paid. If you made charitable donations, gather receipts. If you paid student loan interest or had education expenses, collect those records. If you have dependents, you will need their Social Security numbers and proof of their relationship to you.

Keep any records related to income you reported and deductions you claimed. The IRS does not require you to send these documents with your return, but you must have them if the IRS asks questions later. The IRS can audit returns for up to three years after filing, or longer if there are significant discrepancies.

How to file your 1040

You have three main options for filing. The first is to use tax software — programs like TurboTax, H&R Block, or TaxAct walk you through questions about your income and deductions, then prepare and file your return electronically. Many of these programs are free or low-cost, especially if your income is below a certain level.

The second option is to work with a tax preparer or CPA. They will gather your documents, prepare your return, and file it for you. This costs money, but it can be worth it if your situation is complex — for example, if you are self-employed, own rental property, or have significant investment income.

The third option is to fill out a paper 1040 by hand and mail it to the IRS. This is slower and more error-prone than electronic filing, and the IRS processes paper returns more slowly. You will also wait longer for a refund if you are owed one.

The IRS strongly encourages electronic filing because it is faster, more accurate, and reduces processing errors. If you file electronically and are owed a refund, you typically receive it within 21 days. Paper returns can take six weeks or longer.

Filing deadlines and what happens if you miss them

The deadline to file your 1040 is April 15 of the year following the tax year. For example, you file your 2023 return by April 15, 2024. If April 15 falls on a weekend or holiday, the deadline moves to the next business day. You can request an automatic extension that gives you until October 15, but an extension to file is not an extension to pay — if you owe tax, you should pay by April 15 to avoid penalties and interest.

If you do not file by the deadline and do not have an extension, the IRS will charge you a failure-to-file penalty. This penalty is usually 5 percent of the unpaid tax for each month you are late, up to 25 percent. You will also owe interest on any unpaid tax, calculated daily from the original due date.

If you are owed a refund and you do not file, you will not receive it. The IRS holds unclaimed refunds for three years, after which the money goes to the U.S. Treasury. This is why it is important to file even if you do not owe tax — you may be leaving money on the table.

Who must file a 1040

You must file if your income exceeds the standard deduction for your filing status and age. For 2023, the standard deduction was $13,850 for a single person under 65, $27,700 for a married couple filing jointly, and $20,800 for head of household. These amounts increase each year for inflation, and they are higher if you are 65 or older.

Even if your income is below the standard deduction, you should file if you had taxes withheld from your paychecks or made estimated tax payments. Filing allows you to claim a refund of those overpayments. You should also file if you are owed a refundable tax credit, such as the Earned Income Tax Credit, because the credit can result in a refund even if you owe no tax.

If you are claimed as a dependent on someone else's return, the income threshold is lower. Self-employed people must file if their net self-employment income is $400 or more, regardless of the standard deduction.

Frequently Asked Questions

Can I file my 1040 before I receive all my W-2s and 1099s?

No. You need all your income documents before you file because the IRS receives copies of your W-2s and 1099s and will compare them to what you reported. If there is a mismatch, the IRS will contact you. It is better to wait until you have everything than to file early and have to amend your return later.

What is the difference between a refund and a tax credit?

A tax credit reduces the tax you owe. A refundable credit can result in a refund if the credit is larger than your tax liability. A non-refundable credit can only reduce your tax to zero; any excess is lost. The Earned Income Tax Credit is refundable, which is why low-income workers often receive refunds even though they owe no tax.

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

Yes, if your investment income exceeds the standard deduction. Interest, dividends, and capital gains are all taxable income. You will receive a 1099-INT, 1099-DIV, or 1099-B from your bank or brokerage, and you must report this income on your 1040.

What happens if I make a mistake on my 1040?

You can file an amended return using Form 1040-X. You have three years from the original filing date to amend your return. If the amendment results in a refund, the IRS will send it to you. If it results in additional tax owed, you will receive a bill with interest and possibly penalties.

Can I file my 1040 on my phone?

Most tax software companies offer mobile apps that let you prepare your return on a phone or tablet. However, you will still need to review the full return before submitting it, and some complex situations may be easier to handle on a computer. The IRS itself does not have a filing app — you must use third-party software or a tax preparer.