A divorce decree is signed on January 2. For the prior tax year that ended two days earlier, both spouses are still legally married on December 31. They must file MFJ or MFS for that closed year. The wedding date, the separation date, and the move-out date do not matter. Only the December 31 marital status controls. Filing status is the first line on the return, and getting it right sets the bracket structure, the standard deduction, and the phase-out thresholds for every credit downstream.
HIGH-FREQUENCY: A taxpayer's filing status determines the standard deduction, the bracket widths, and most credit phase-out thresholds. Five statuses exist. From most to least favorable: Married Filing Jointly (MFJ), Qualifying Surviving Spouse (QSS), Head of Household (HoH), Single, and Married Filing Separately (MFS).
Marital status is determined on the last day of the tax year. If a taxpayer is married on December 31, the only options are MFJ or MFS (HoH is possible only under a narrow "considered unmarried" exception).
Common mistakes
- Filing Head of Household while still married on December 31. A taxpayer must be unmarried on December 31 or meet the "considered unmarried" exception (lived apart from spouse for the last 6 months of the year). A couple that separated in October does not qualify.
- Treating a qualifying parent like every other qualifying person. A parent does not have to live with the taxpayer to qualify the taxpayer for HoH. The taxpayer just needs to pay more than 50% of the parent's household upkeep (including a separate apartment or nursing home).
- Letting one MFS spouse itemize while the other takes the standard deduction. When MFS spouses are filing, both must itemize or both must take the standard. If one spouse itemizes, the other has $0 standard deduction and must itemize even if they have no itemized deductions to claim.
Bottom line
- Marital status is fixed on December 31; married that day means MFJ or MFS, with HoH available only through the considered-unmarried exception.
- The considered-unmarried exception requires living apart from the spouse for the last 6 months of the year.
- HoH requires unmarried status, a qualifying person, and paying more than 50% of household costs; a qualifying parent need not live with the taxpayer.
- MFS spouses must match deduction methods, so if one itemizes the other gets a $0 standard deduction; MFS also disqualifies the EITC and shrinks many phase-out thresholds.
Exam shortcut
When a question asks for filing status, start with December 31 marital status. If married, the answer is MFJ or MFS, never HoH (unless the apart-for-the-last-6-months exception applies). If widowed, check for the QSS window (years 1-2 after death + dependent child). If unmarried, screen for HoH (qualifying person + >50% household costs). Otherwise Single.
The full lesson (about 2,517 words, 17 min read) adds 1 worked example, all 6 common mistakes, a self-check, free in the app.
Learning objectives
- IV.E1
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