Minimum Income

• As of the 2010 tax year, if you have self-employment income over $400, you must file your federal income taxes. For other income earners, filing requirements depend on marital status, dependent status and age. For example, a single person under age 65 who earned $9,350 or more must file 2010 tax-year taxes, while single people 65 and older must file only if earning $10,750 or more. That limit drops to $3,650 if you are married and filing separately at any age, but raises if you are married and filing jointly, a widower with a dependent child or if you're filing as the head of household. These numbers only apply to the 2010 tax year. For other years, visit the "Individuals" section on the IRS website to locate updated limits, generally listed in Publication 17.
  
  

Dependents

• If you are a dependent on someone else's tax return, you are subject to different minimum tax amounts that determine whether you must file your own taxes independently. For example, a single, dependent 17-year-old must file if his earned income was more than $5,700 in the 2010 tax year. If the same person had a mix of earned and unearned income, such as interest income or dividends, there are special calculations to determine whether she must file based on the exact amounts of both income types. Disabilities such as blindness are also taken into consideration for the established minimum filing requirements. You can find the current schedule of minimums and calculations in IRS publication 929.
  
  

Significant Tax Events

• Your earned income isn't the only factor in whether you have to file. Regardless of your earned income level, you must file a federal tax return if you sold your home during the tax year or are subject to the Alternative Minimum Tax. Some states may also require you to file state tax returns regardless of your earned income amount, so check with your state's department of revenue for your state income tax filing responsibilities.
  
  

When Filing Isn't Necessary

• If you have earned income less than the required minimum for your marital status, age and dependent status and no unearned income or other significant tax events, you are not required to file a tax return. However, you may be able to get money back from the government in the form of a tax refund, depending on how much your employer withheld from your wages for federal taxes, based on your W-4 form. If you want to receive this refund, you will need to file. You have up to three years after the tax deadline to file your tax return to claim refunds owed to you.