There are five filing statuses with the IRS and some taxpayers may qualify for more than one status. Understanding which status is more advantageous is important. In the video above I discuss each status briefly. As we go over the 1040 line by line you will see what status provides different benefits depending on the item being discussed.
Single To file single you must not be married at the end of the tax year or you must be legally separated or divorced. You may also file single if you were widowed before the beginning of the tax year. Although you may qualify for single status there are chances you may qualify for other statuses too which would have a higher standard deduction and other benefits.
Married Filing Jointly To qualify for this status you need to be married and living together or married and living separate, but not separated or divorced. A common law marriage may be recognized for this status. If your spouse dies during the year you can still file married filing jointly that year. This provides tax benefits for the surviving spouse over other statuses.
Married Filing Separately This is similar to married filing jointly except the taxpayers file separate returns and therefore get lower standard deductions, etc. One thing to keep in mind here is that a taxpayer who files separately from their spouse must take the standard deduction if their spouse does, if their spouse itemizes they must also itemize. This is to prevent taxpayers from filing separate so one can take a standard deduction and the other can claim all of the itemized deductions. In general this status is not more advantageous than married filing jointly, although there are circumstances in which it can be.
Head of Household For this status you must be married at the end of the tax year, have a qualifying dependent who lives with you, and have paid more than half of the upkeep for the home in which you both reside. Children are not the only dependents that may qualify a taxpayer for this status, there are other dependents such as parents and other relatives that may qualify a taxpayer if they meet certain requirements. There are also instances where a taxpayer may be "considered unmarried" and can file as head of household.
Qualifying Widower A taxpayer who lost their spouse can claim married filing jointly the year the spouse passes, the following two years they are eligible to file as a qualifying widower if they remain unmarried, have a qualifying dependent, and pay more than half the upkeep of their home. The qualifying widower gives a larger tax advantages than the head of household to help the taxpayer during the transition after their spouses death.
This isn't an exhaustive list of qualifications for each filing status, but the IRS provides a multitude of resources on these kinds of topics. Take a look at the following for more information:
The IRS interactive tax assistant: What is my filing status:
A PDF lesson from the IRS through the VITA program: