Each filing status describes a certain group of taxpayers:

• Single, which includes anyone not married, including those who are widowed, divorced, or legally separated as of the last day of the year
• Married filing jointly, which includes married couples, people with a legally recognized common law marriage, and anyone whose spouse died during the tax year
• Married filing separately, which includes legally married couples, whether or not they live together
• Head of household, which refers to an unmarried adult who maintains a home and supports a qualifying relative
• Qualifying widow or widower with a dependent child, which includes widowed people in the two years following the year in which their spouse died

You must use a status that describes your situation accurately as the IRS defines it. But if you could fit in two categories, you have the right to choose the one that results in your owing the least tax. For example, someone who is entitled to use head of household status usually pays less tax on an equivalent amount of income than he or she would pay filing as a single person.