Using the right tax table
Your filing status determines which tax table you must use to compute your income tax. According to the IRS, your filing status should reflect your marital status on Dec. 31, regardless of your status throughout the rest of the year. The federal government divides filing status for tax purposes into four categories: single, married filing separately, married filing jointly or head of household. If you are a qualifying widow or widower, you can use the married filing jointly category.
You should choose the category that gives you the lowest overall tax liability if you qualify for more than one. For example, if you are eligible to file as head of household, then you are also eligible to file as single. However, choosing to file as head of household will save you a significant amount of income tax in most cases.