A guide to Form 1040

The basic income tax form, line by line

Derek Silva

Updated December 31, 2020

infoEditorial Disclosure


  • Everyone uses the same Form 1040, except nonresident aliens

  • Form 1040 is short at just 24 lines, but you need to attach additional schedules (forms) if you have certain types of income, credits, or deductions

  • You can file your 2019 taxes between Jan. 27, 2020, and July 15, 2020

  • All federal income taxes go to the Internal Revenue Service (IRS), but your state may have its own income taxes and forms

IRS Form 1040 is the basic income tax form that almost every taxpayer in the U.S. must use. There are two main exceptions: nonresident aliens use Form 1040-NR and single filers whose earned income from the year is less than the standard deduction likely don’t need to file a return. Seniors also have the option to file Form 1040-SR. It’s nearly identical to the standard 1040, but it’s language is tailored to taxpayers who are 65 and older.

The 2020 Form 1040 is a two-page form that’s greatly simplified from years past because of the 2017 tax reform. However, there are many additional forms and schedules (a fancy word for form) you may need to attach.

How to file Form 1040

As long as you're filing a current income tax return, the easiest way to file is electronically through an online tax filing service.

E-filing is safer because you don’t have to worry about anything getting lost in the mail. It's easier because online e-filing services will guide you through the filing process. The IRS estimates that 21% of paper returns have errors, while less than 1% of e-filed returns have mistakes. E-filing also takes the IRS significantly less time to process. Opting for direct deposit means your refund arrives weeks (or even months) sooner.

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If you’re filing back taxes for a previous tax year, you need to fill out a paper form and mail it to the IRS.

Unsure of the best way to file? Start with our complete guide to filing taxes.

When to file your 1040

You can start filing your 2020 taxes on January 2021. Then you have until April 15, 2021 (Tax Day), to submit your return to the IRS.

If you need more time, you can request a six-month tax extension from the IRS. This gives you until October 15, 2021 to file. Everyone automatically gets an extension if they request one. Just keep in mind that if you owe taxes, you still need to pay them by Tax Day. The extension gives you more time to file, but not more time to pay. Failing to pay your bill on time will result in penalties and interest.

Where to mail Form 1040

Anyone can file a paper form instead of e-filing, but the IRS does not recommend it. It takes longer to process and is more prone to mistakes. If you’re filing back taxes or an amended tax return, you will need to file a paper form. Where you send a paper form depends on where you live. (Amended returns may have different mailing addresses. See the Form 1040X instructions for more.)

ResidenceMailing address if you're getting a refundMailing address if you are making a payment
Alabama, Georgia, Kentucky, New Jersey, North Carolina, South Carolina, Tennessee, VirginiaDepartment of the Treasury

Internal Revenue Service

Kansas City, MO 64999-0002 | Internal Revenue Service

P.O. Box 931000

Louisville, KY 40293-1000 | | Alaska, Arizona, California, Colorado, Hawaii, Idaho, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming | Department of the Treasury

Internal Revenue Service

Fresno, CA 93888-0002 | Internal Revenue Service

P.O. Box 7704

San Francisco, CA 94120-7704 | | Arkansas, Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Montana, Nebraska, North Dakota, Ohio, Oklahoma, South Dakota, Wisconsin | Department of the Treasury

Internal Revenue Service

Fresno, CA 93888-0002 | Internal Revenue Service

P.O. Box 802501

Cincinnati, OH 45280-2501 | | Connecticut, District of Columbia, Maryland, Pennsylvania, Rhode Island, West Virginia | Department of the Treasury

Internal Revenue Service

Ogden, UT 84201-0002 | Internal Revenue Service

P.O. Box 37910

Hartford, CT 06176-7910 | | Delaware, Maine, Massachusetts, Missouri, New Hampshire, New York, Vermont | Department of the Treasury

Internal Revenue Service

Kansas City, MO 64999-0002 | Internal Revenue Service

P.O. Box 37008

Hartford, CT 06176-7008 | | Florida, Louisiana, Mississippi, Texas | Department of the Treasury

Internal Revenue Service

Austin, TX 73301-0002 | Internal Revenue Service

P.O. Box 1214

Charlotte, NC 28201-1214 | | A foreign country, a U.S. possession or territory (or if you are a dual-status alien, have an APO, FPO address, you file Form 2555, 2555-EZ, or 4563) | Department of the Treasury

Internal Revenue Service

Austin, TX 73301-0215 | Internal Revenue Service

P.O. Box 1303

Charlotte, NC 28201-1303 |

Filing for previous years

If you have back taxes — taxes from a previous year — you can only file by mailing a physical form. You cannot e-file federal tax returns from previous years.

The Form 1040 had three versions for tax years before 2018. The 1040-EZ was for simple tax returns, the 1040-A allowed filers to claim additional tax credits, and the standard 1040 covered more complex situations like filers who itemize deductions. (This is all in addition to 1040-NR and 1040NR-EZ for nonresident aliens.)

The IRS website has all previous years’ tax forms and instructions. Make sure you are following the correct instructions. Unless you have a very simple tax return, you may want to work with a tax preparer.

If you need copies of old tax forms, like 1099s or W-2 forms, you can get those from the IRS by requesting a free tax transcipt.

Line-by-line Form 1040 instructions

The 2020 IRS Form 1040 is a relatively simple two-page form. There are a few sections at the beginning and then 24 numbered lines. You will need to add other forms to claim tax credits and any deductions beside the standard deduction.

If you’re e-filing, the filing service will walk you through the entire process, and attach all of the necessary documents. However, it’s still useful to understand exactly what you’re doing when you file.

Personal information

The first section of the form (before the numbered lines start) is for your personal information. This includes your filing status, name, address, and Social Security number (SSN). There’s also room for your spouse’s information, if you’re filing a joint return. Aliens can enter an Individual Taxpayer Identification Number (ITIN) on the SSN line.

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Next there is a section about your standard deduction. The amount of your standard deduction varies based on your filing status, age, and whether or not you’re blind. This section of the 1040 has seven boxes to help show the amount of your standard deduction. Check the ones that apply to you. Joint filers should check the boxes if they apply to either spouse.

The section on your dependents has room for each of their SSNs, their relationship to you, and then a box you can check if the dependent qualifies you for the child tax credit or credit for other dependents.

Learn more about who you can claim as a dependent.

Calculating your taxable income

Lines 1 through 7 help you calculate your total income for the year. Each line asks you to enter the amount you made from a different type of income. Then you will make any necessary adjustments before determining how much of your income was actually taxable. If a line doesn't apply to you, either leave it blank or write in a zero. You can also round all values to the nearest dollar (whether up or down) before writing them on a line.

Line 1 is for all income reported on your W-2 forms, which you should attach when you file.

Line 2 has two parts, one for tax-exempt interest (mainly municipal bonds) and one for taxable interest. Taxable interest includes income from a 1099-INT or 1099-OID. You will need to attach Schedule B if you had $1,500 or more of taxable interest or ordinary dividends.

Line 3 is where you list income from dividends. Line 3a is for qualified dividends and 3b is for ordinary dividends. You will need to attach Schedule B if you have income from a 1099-DIV. (Learn more about the types of 1099 forms.)

Line 4 is for income from IRA distributions, pensions, or annuities. You will write the total income from these sources and then how much is actually taxable.

Line 5 is for your income from Social Security benefits. (Read more about Social Security payment schedules.)

Line 6 asks about your capital gains or losses from the past year. Two common reasons to have capital gains are that you sold stock investments or you sold your house. You likely received a 1099-B or 1099-S if you had capital gains, and you will probably need to attach Schedule D to your 1040. (Start with our guide to capital gains tax.)

Line 7 has two parts. Line 7a is where you write any additional income you made during the year. This includes everything not included in the previous lines. If you have other income, you will also need to attach Schedule 1. Line 7b is where you add up all the lines thus far to find your total income, also known as your gross income.

Line 8 is where you write how much your income should be adjusted, if at all. Income adjustments include certain expenses you incurred that are eligible to exclude from your income. You track these on Schedule 1 and common adjustments to income include alimony payments, a deduction for IRA contributions, and the student loan interest deduction. Your income after subtracting adjustments is your adjusted gross income (AGI).

Line 9 asks you to write in either the amount of the standard deduction or your itemized deductions. Most people will take the standard deduction, which varies based on your filing status and is listed on the form right next to this line (though you will get an additional deduction if you're over age 65 or blind). Only about 10% of taxpayers qualify to itemize after the 2017 tax reform. If you itemize, complete Schedule A.

Line 10 is for anyone using the qualified business income deduction. You will need to attach either Form 8995 or Form 8995-A to take this deduction.

On line 11, add the previous lines to find your taxable income, which is your adjusted income minus the qualified business income deduction.

Calculating your annual tax bill

Line 12a has you calculate how much tax you owed on your taxable income. To do this, add line 11 with any additional income you had, as explained in the next paragraph. If your taxable income was less than $100,000, use the 2019 Tax Table in the Form 1040 instructions to simply look up how much tax you owe. Use the 2019 Tax Computation Worksheet in the instructions if your taxable income was $100,000 or more.

Before completing line 12a, there are three boxes on line 12 where you account for certan types of aditional income you may have had. These include a child’s income that you’re claiming as your own (also complete Form 8814); a lump-sum distribution from an IRA, pension plan, or tax-advantaged account (also complete Form 4972); any excess advance payments for the health coverage tax credit (HCTC); certain kinds of business income from a partnership; and investment income from a foreign-owned corporation. See the 1040 instructions for more details and make sure to include all this income in your calculation for line 12a. (Remember that the lump-sum disbursement from a life insurance policy is tax free.)

Line 12b is where you determine your 2019 tax liability — the total income tax you owed. Simply add line 12a, line 3, and the total from Schedule 2, if you used that form.

Claiming credits and deductions

After finding your tax liability, lines 13 through 16 of the 1040 consider any tax credits you should receive because you cared for dependents. Lines 17-19 consider how much tax you already paid (including out of your regular paychecks) and other tax credits you may qualify for. Credits directly reduce your tax liability. The two main results of this section are the amount you already pay in tax and the amount of tax you owe after accounting for tax credits.

Line 13 is for claiming the child tax credit and the credit for any non-child dependents. You will need to complete and attach From 8862.

Subtract line 13 from 12 and write the result on line 14. If it's less than 0, just write 0. The child tax credit is nonrefundable, which means you will not get any money back if the amount you owe is less than 0.

Line 15 is for reporting additional taxes you owe, including the self-employment tax, the alternative minimum tax, and any repayment you need to make for excess advanced premium tax credit. Any type of tax you report here will require attaching an addition form.

Add lines 14 and 15. The result goes on line 16 and tells you your total tax. This is the amount of tax you actually owe for the year.

Line 17 asks for the income taxes that employers already withheld from your pay. Withholding will be on your W-2 forms and 1099 forms.

Line 18 has four parts and applies to people who can claim certain refundable tax credits: the earned income credit (EIC), additional child tax credit (ACTC), and American opportunity tax credit (AOTC). These credits directly decrease the amount of tax you owe for the year. In the eyes of the IRS, the value you get from these credits is the same as already having paid that amount through income tax withholding.

Line 19 asks you to add the totals from lines 17 and 18. The result is called your total payments, which means the total tax you have already paid.

(Further reading: the difference between tax credits and deductions)

Calculating your tax refund or bill

The next five lines are where you write in the total amount of your refund or tax bill.

If the total tax you paid (line 19) is more than the total tax you owed (line 16), you will get a refund. Calculate your refund amount by subtracting line 16 from 19 and then writing the result on line 20.

Line 21 is for direct deposit of your refund. You will write in your bank account number, the bank routing number, and what kind of account it is. You can divide the refund among multiple accounts or opt for a paper check with Form 8888. (Learn more: Should you be using a checking or savings account?).

Line 22 is for people who want to apply some or all of their refund to their 2020 estimated taxes.

Anyone who owes money will fill out line 23 by subtracting line 19 from 16. Any penalty you owe on that bill goes on line 24. You will owe a penalty if your tax bill is $1,000 or more. You could also owe a penalty if the tax you paid during the year was less than 90% of the total you owed.

Sign, seal, deliver

The final part of the 1040 form is for signatures. You will sign, date, and then write your occupation. Any tax preparer you worked with will also sign. If you want to allow anyone to talk with the IRS about the return on your behalf, you can add their name in the “Third Party Designee” section. The designee can include a friend or family member who the IRS is authorized to contact if they have questions about your return or missing forms.

Anyone mailing their return can find the proper mailing address in the table from earlier in this article.


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Personal Finance Expert

Derek Silva

Personal Finance Expert

Derek is a personal finance editor at Policygenius in New York City, and an expert in taxes. He has been writing about estate planning, investing, and other personal finance topics since 2017. His work has been covered by Yahoo Finance, MSN, Business Insider, and CNBC.

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