Same-sex couples who file a joint federal income tax return must continue to file Michigan personal income tax returns using the single filing status. State law limits a joint return to a married couple who are a husband and wife. The state constitution defines marriage as the union of one man and one woman. Under state law, the phrase “husband and wife” means a man and woman who are married to each other.
Each individual who has income attributable to Michigan and who filed a joint return for federal income tax purposes as a same-sex couple must separately report adjusted gross income for Michigan as a single filer. Each individual must recalculate the federal adjusted gross income as if that person had filed a single tax return for federal income tax purposes. The Department of Treasury will provide a worksheet for the calculation.
Notice to Taxpayers: Same-Sex Couples Filing Joint Federal Income Tax Returns Must File Michigan Income Tax Returns As Single Filers, Michigan Department of Treasury, September 2013