How much do you have to make to file a federal tax return?

Generally, Single under age 65 must file when your gross income is at least $8,950 for 2008 ($9,350 for 2009). Married Filing Jointly under age 65 must file when your gross income is at least $17,900 ($18,700 for 2009). Married Filing Separately must file when your gross income is at least $3,500 ($3,650 for 2009). Head of Household under age 65 files when your income is at least $11,500 ($12,000 for 2009). Qualifying widow(er) under age 65 with dependent child files when your income is at least $14,400 ($15,050 for 2009). Dependents under age 65 must file if your earned income is over $5,450 for 2008 ($5,700 for 2009).

Even if you're not required to file, you should file under certain circumstances. One, you're filing for a refund of withheld income tax because you owe no tax. Two, you're eligible for certain credits (earned income, making work pay, additional child tax credit, etc.).