Who must file taxes?
If your gross income was as least as great as the amount shown below and you are under 65 years old, you must file an income tax return
Single - $9,500
Head of Household - $12,200
Married Filing Jointly - $19,000
Married Filing Separately - $ 3,700
Qualifying Widow or Widower - $15,300
Note that slightly higher gross income limits apply to those 65 or older or blind. Consult Chart A in the 1040 Instructions for further details.
Even if you are not required to file a return, it might be beneficial to do so, especially if you had federal income tax withheld or if you qualify for the Earned Income Credit, Additional Child Tax Credit, American Opportunity Credit, or other credits and deductions. In these situations, filing a return could very well result in a refund.
Whether a dependent must file a tax return largely depends on their level of income. Single dependents under age 65 with earned income over $5,800 and unearned income over $950 must file. Different limits apply to married dependents and those 65 and older or blind. Refer to IRS Publication 929 for further details.