Single(p20)

Your filing status is single if, on the last day of the year, you are unmarried or legally separated from your spouse under a divorce or separate maintenance decree, and you do not qualify for another filing status. To determine your marital status on the last day of the year, see Marital Status, earlier.

Your filing status may be single if you were widowed before January 1, 2010, and did not remarry before the end of 2010. However, you might be able to use another filing status that will give you a lower tax. See Head of Household and Qualifying Widow(er) With Dependent Child, later, to see if you qualify.

You can file Form 1040EZ (if you have no dependents, are under 65 and not blind, and meet other requirements), Form 1040A, or Form 1040. If you file Form 1040A or Form 1040, show your filing status as single by checking the box on line 1. Use the Single column of the Tax Table or Section A of the Tax Computation Worksheet to figure your tax.