If you are married, then you and your spouse can filing a joint tax return. You are considered married if you are legally married on the last day of the year. In order to file jointly, both you and your spouse must agree to file a joint tax return, and both must sign the return. Married Filing Jointly (MFJ) provides more tax benefits than filing a separate return.
The IRS advises that, "If you and your spouse decide to file a joint return, your tax may be lower than your combined tax for the other filing statuses. Also, your standard deduction (if you do not itemize deductions) may be higher, and you may qualify for tax benefits that do not apply to other filing statuses" (from Publication 501, "Married Filing Jointly").
What's a Joint Tax Return?By filing a joint tax return, both spouses report all their income, deductions, and credits on one tax return. Both spouses must sign the return, and both spouses accept full responsibility for the accuracy and completeness of the information reported on the tax return. If the tax is unpaid, each spouse is held personally responsible for the payment. If the tax return is audited by the IRS, each spouse will be held responsible for providing documents to demonstrate the accuracy of the tax return. In other words, each spouse is held jointly and severally liable for the tax on a jointly filed tax return.
The IRS cautions, "Both of you may be held responsible, jointly and individually, for the tax and any interest or penalty due on your joint return. One spouse may be held responsible for all the tax due even if all the income was earned by the other spouse" (from Publication 501).
The IRS may grant relief from joint liability for taxes through innocent spouse relief, separation of liability, or equitable relief. Refer to Publication 971 (Innocent Spouse Relief) for additional information about these tax relief programs.
Deceased SpouseIf your spouse died during the year, you can still file a joint return for that year. In the following years, you can file as a surviving spouse, as head of household, or as a single taxpayer. The IRS explains, "If your spouse died during the year, you are considered married for the whole year and can choose married filing jointly as your filing status" (from Publication 501).
Filing Joint versus Separate ReturnsFiling a separate return provides relief from joint liability for taxes. However, married taxpayers who file separately are not eligible for many tax deductions and credits, and have higher tax rates. In general, it is more advantageous to file a joint return.
Same-Sex Married CouplesSame-sex married couples are allowed to file a joint tax return using the married filing jointly status. Or if they choose, they can file separate returns using the married filing separately status. Previously, the IRS did not allow same-sex married couples to file jointly as section 3 of the Defense of Marriage Act only recognized marriages between a man and woman. The Supreme Court struck down section 3 of the Defense of Marriage Act as unconstitutional. In Revenue Ruling 2013-17 (pdf, 15 pages), the IRS said "For Federal tax purposes, the terms 'spouse,' 'husband and wife,' 'husband,' and 'wife' include an individual married to a person of the same sex if the individuals are lawfully married under state law, and the term 'marriage' includes such a marriage between individuals of the same sex."
Further, same-sex married couples are considered legally married as long as they were married in a state that recognizes same-sex marriage. Thus, same-sex married couples are considered married for tax purposes even if they are legally married in one state and reside in another state that does not recognize same-sex marriage. In Revenue Ruling 2013-17, the IRS takes the position, "For Federal tax purposes, the Service adopts a general rule recognizing a marriage of same-sex individuals that was validly entered into in a state whose laws authorize the marriage of two individuals of the same sex even if the married couple is domiciled in a state that does not recognize the validity of same-sex marriages."
Domestic Partners and Civil UnionsTaxpayers who are in a registered domestic partnership or a civil union are not considered to be married, and so will need to file their tax returns as unmarried persons: using either the single or head of household filing status. In Revenue Ruling 2013-17, the IRS takes the position, "For Federal tax purposes, the terms 'spouse,' 'husband and wife,' 'husband,' and 'wife' do not include individuals (whether of the opposite sex or the same sex) who have entered into a registered domestic partnership, civil union, or other similar formal relationship recognized under state law that is not denominated as a marriage under the laws of that state, and the term 'marriage' does not include such formal relationships."
Furthermore, domestic partners and persons in a civil union who reside in a community property state may need to allocate income and deductions between each partner. This applies to domestic partners in the community property states of Washington, Nevada, and California.