The Internal Revenue Service (IRS) Publication 17 spells out the requirements for filing. Generally, if

you are a U.S. citizen or resident, whether you must file a return depends on three factors.

1. Your gross income.
2. Your filing status.
3. Your age.

To find out whether you must file, see Table 1-1, Table 1-2, and Table 1-3. Even if no table shows that you must file, you may need to file to get money back. See Who Should File, later.

Gross income.

This includes all income you receive in the form of money, goods, property, and services that isn’t exempt from tax. It also includes income from sources outside the United States or from the sale of your main home (even if you can exclude all or part of it). Include part of your social security benefits if:

1. You were married, filing a separate return, and you lived with your spouse at any time during 2021; or
2. Half of your social security benefits plus your other gross income and any tax-exempt interest is more than $25,000 ($32,000 if married filing jointly).

If either (1) or (2) applies, see the Instructions for Form 1040 or Pub. 915, Social Security and Equivalent Railroad Retirement Benefits, to figure the social security benefits you must include in gross income.

Common types of income are discussed in Part Two of this publication.

Community property states.

Community property states include Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin. If you and your spouse lived in a community property state, you must usually follow state law to determine what is community property and what is separate income. For details, see Form 8958 and Pub. 555.

Nevada, Washington, and California domestic partners.

A registered domestic partner in Nevada, Washington, or California must generally report half the combined community income of the individual and his or her domestic partner. See Pub. 555.

Self-employed individuals.

If you are self-employed, your gross income includes the amount on line 7 of Schedule C (Form 1040), Profit or Loss From Business; and line 9 of Schedule F (Form 1040), Profit or Loss From Farming. See Self-Employed Persons, later, for more information about your filing requirements.

Filing status.

Your filing status depends on whether you are single or married and on your family situation. Your filing status is determined on the last day of your tax year, which is December 31 for most taxpayers. See chapter 2 for an explanation of each filing status.

Age.

If you are 65 or older at the end of the year, you can generally have a higher amount of gross income than other taxpayers before you must file. See Table 1-1. You are considered 65 on the day before your 65th birthday. For example, if your 65th birthday is on January 1, 2022, you are considered 65 for 2021.

Table 1-1. 2021 Filing Requirements for Most Taxpayers INDIVIDUALS

IF your filing status is…	AND at the end of 2021 you were…*	THEN file a return if your gross income was at least…**
Single	under 65	$12,550
	65 or older	$14,250
Married filing jointly***	under 65 (both spouses)	$25,100
	65 or older (one spouse)	$26,450
	65 or older (both spouses)	$27,800
Married filing separately	any age	$5
Head of household	under 65	$18,800
	65 or older	$20,500
Qualifying widow(er)	under 65	$25,100
65 or older	$26,450

Source: IRS Publication 17