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, and
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.

 Gross income. This includes all income you receive in the form of money, goods, property, and services that is not 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 2013; 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 1040A, or Publication 915, Social Security and Equivalent Railroad Retirement Benefits, to figure the social security benefits you must include in gross income.

Community income. If you are married and your permanent home is in a community property state, half of any income described by state law as community income may be considered yours. This affects your federal taxes, including whether you must file if you do not file a joint return with your spouse. See Publication 555, Community Property, for more information.
Nevada, Washington, and California domestic partners. A registered domestic partner in Nevada, Washington, or California generally must report half the combined community income of the individual and his or her domestic partner. See Publication 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; line 1 of Schedule C-EZ (Form 1040), Net Profit From Business; and line 9 of Schedule F (Form 1040),
Profit or Loss From Farming.