The first step to filing your federal income tax return is to determine which filing status to use. Your filing status is used to determine your filing requirements, standard deduction, eligibility for certain credits and deductions, and your correct tax. There are five filing statuses: Single, Married Filing Jointly, Married Filing Separately, Head of Household and Qualifying Widow(er) with Dependent Child.

Here are eight facts about the five filing status options the IRS wants you to know so that you can choose the best option for your situation.

Your marital status on the last day of the year determines your marital status for the entire year.
If more than one filing status applies to you, choose the one that gives you the lowest tax obligation.
Single filing status generally applies to anyone who is unmarried, divorced or legally separated according to state law.
A married couple may file a joint return together. The couple’s filing status would be Married Filing Jointly.
If your spouse died during the year and you did not remarry during 2010, usually you may still file a joint return with that spouse for the year of death.
A married couple may elect to file their returns separately. Each person’s filing status would generally be Married Filing Separately.
Head of Household generally applies to taxpayers who are unmarried. You must also have paid more than half the cost of maintaining a home for you and a qualifying person to qualify for this filing status.
You may be able to choose Qualifying Widow(er) with Dependent Child as your filing status if your spouse died during 2008 or 2009, you have a dependent child and you meet certain other conditions.

There’s much more information about determining your filing status in IRS Publication 501, Exemptions, Standard Deduction, and Filing Information. Publication 501 is available at http://www.irs.gov or by calling 800-TAX-FORM (800-829-3676). You can also use the Interactive Tax Assistant on the IRS website to determine your filing status. The ITA tool is a tax law resource on the IRS website that takes you through a series of questions and provides you with responses to tax law questions.

Link:

Publication 501, Exemptions, Standard Deduction, and Filing Information (PDF 196K)