What States Recognize Same-Sex Marriage for Tax Purposes?

Nationwide Recognition for State Tax Filing

The universal recognition of same-sex marriage for state tax purposes is a direct result of the 2015 U.S. Supreme Court decision in Obergefell v. Hodges. This ruling mandated that all states must license and recognize marriages between two people of the same sex. Consequently, states are required to extend all rights and responsibilities of marriage to same-sex couples, which includes the regulations and benefits associated with filing state income taxes.

Before this decision, and an earlier 2013 case, United States v. Windsor, which invalidated parts of the federal Defense of Marriage Act (DOMA), tax filing was a patchwork of differing state laws. Couples could be considered married for state tax purposes in one state but not in another, and not for federal purposes. The Supreme Court’s decisions aligned state and federal recognition, ensuring that a marriage legally performed in any state is recognized by all other states and the federal government for tax filing.

State Tax Filing Statuses for Married Couples

For legally married couples, state tax filing obligations are directly linked to their federal tax return. When preparing their annual IRS Form 1040, a married couple must choose between two primary filing statuses: Married Filing Jointly (MFJ) or Married Filing Separately (MFS). Nearly all states with an income tax require couples to use the same filing status on their state return that they selected for their federal return, as state tax calculations often begin with figures from the federal return.

The MFJ status combines both spouses’ incomes and deductions onto a single return. This status typically offers more favorable tax brackets and access to a wider range of tax credits and deductions, often resulting in a lower overall tax liability. In contrast, the MFS status requires each spouse to file their own return, reporting their own income and deductions. MFS usually leads to a higher combined tax bill and disqualifies the filers from certain tax benefits.

Treatment of Registered Domestic Partnerships and Civil Unions

A distinction exists between marriage and other legal unions like Registered Domestic Partnerships (RDPs) and Civil Unions. The Internal Revenue Service (IRS) does not recognize RDPs or civil unions as marriage for federal tax purposes. This means partners in these arrangements cannot file as married; they must file their federal Form 1040 using the “Single” or, if eligible, “Head of Household” filing status.

While not recognized federally, a select number of jurisdictions grant married-like status to these unions for state income tax purposes. These jurisdictions require registered domestic partners or members of a civil union to file their state tax returns using a married status. They include:

• California
• Connecticut
• District of Columbia
• New Jersey
• Oregon
• Vermont

This dual-status system imposes a unique compliance requirement. To file their state return, these partners must first complete their individual federal returns as single individuals. They must then prepare a pro forma, or “as-if,” federal tax return as if they were filing jointly or separately as a married couple. This mock federal return is not filed with the IRS but is used solely to calculate the figures needed to properly complete their state income tax return using a married status. This process ensures state tax is calculated based on the combined financial picture, even though federal tax is assessed individually.