Filing Status (2025)

Overview

Five filing statuses. Marriage status on December 31 determines the year (except death or annulment). If eligible for multiple statuses, choose the one producing lowest tax.

1. Single

Qualify if on Dec 31 you are:

• Never married, OR
• Legally divorced, OR
• Legally separated under a divorce or separate maintenance decree

2. Married Filing Jointly (MFJ)

• Both spouses must agree and sign
• Joint and several liability — each spouse is fully responsible for all tax due
• Surviving spouse can file MFJ in year of spouse's death (if not remarried that year)
• Nonresident alien spouse: can elect to be treated as US resident (must report worldwide income, needs ITIN)
• Common law marriage recognized if valid under state law (CO, DC, IA, KS, MT, OK, RI, TX)

3. Married Filing Separately (MFS)

• Each spouse reports own income, deductions, credits
• Standard deduction: $15,750, BUT if spouse itemizes, MFS filer must also itemize (or take $0 standard deduction)
• Capital loss limit: $1,500 (half of MFJ)
• No student loan interest deduction
• No EITC, no child/dependent care credit, no adoption credit (generally)
• Can amend from MFS to MFJ within 3 years; cannot switch from MFJ to MFS after due date
• Why use MFS: high medical expenses (lower AGI → more deductible), protect refund from spouse's debts

4. Head of Household (HoH)

Must meet ALL three tests:

Test 1 — Unmarried or "considered unmarried":

• Single, divorced, or legally separated on Dec 31, OR
• Married but lived apart from spouse for last 6 months of year + paid >50% of home costs + qualifying child lives with you

Test 2 — Paid >50% of home costs:

• Rent, mortgage interest, property taxes, utilities, home insurance, repairs, food eaten at home

Test 3 — Qualifying person lived with you >50% of year:

• Qualifying child (son, daughter, stepchild, foster child, sibling, or descendant)
• Qualifying relative (parent — doesn't need to live with you)
• Exception: dependent parent can live elsewhere

5. Qualifying Surviving Spouse (QSS) / Qualifying Widow(er)

Available for 2 years after year of death if:

• Qualified for MFJ in year of death
• Not remarried by end of current year
• Have a dependent child (son, daughter, stepchild, or adopted child) living with you all year — NOT a foster child
• Paid >50% of home costs

Same tax rates and standard deduction as MFJ.

Timing trap: If spouse died in 2024, QSS available for 2025 and 2026. Switches to Single/HoH in 2027.

Annulment

• Treated as if marriage never existed
• Must file amended returns as Single for all open years (generally 3-year statute)
• If MFJ returns already filed, amend with Form 1040-X

Registered Domestic Partners / Civil Unions

• Federal law does NOT allow RDPs or civil-union partners to file MFJ — treated as unmarried (Single, or HoH if eligible) for federal purposes, even if state allows joint filing.
• Common-law marriage IS recognized federally if valid under state law (CO, DC, IA, KS, MT, OK, RI, TX recognize; same-sex common-law marriages recognized by some states).

Tax Residency Status (Aliens)

IRS classifies non-citizens as resident alien or nonresident alien (NRA). Resident aliens are taxed like citizens on worldwide income. NRAs are taxed only on US-source income. Dual-status aliens are part-year resident/part-year NRA (typically arrival/departure years).

Green Card Test

Lawful permanent resident (holds green card) at any time during the year → resident alien for the full year.

Substantial Presence Test

Present in US:

• ≥31 days during current year, AND
• ≥183 days over 3-year period = current year days + 1/3 × prior year days + 1/6 × 2 years prior

Exempt Individuals (days do NOT count)

• Foreign government officials
• Teachers/trainees/researchers (J/Q visas — typically exempt first 2 calendar years, 5 for students)
• Students (F/J/M/Q visas — exempt first 5 calendar years; any partial calendar year counts as a full year)
• Professional athletes in charitable sports events (only competition days excluded)
• Commuters from Canada/Mexico with closer connection to home country
• Days unable to leave due to medical condition arising while in US

Nonresident Spouse Election

NRA married to a US citizen/resident may elect to be treated as a resident → file MFJ and report worldwide income. Must attach election statement; NRA spouse needs ITIN. If spouse dies or election revoked, cannot revert.

Dual-Status Aliens

Day-of-year status on Dec 31 controls. NRA period → only US-source income. Resident period → worldwide income. Dual-status cannot file MFJ (unless NRA spouse elects residency). Form 1040 + Form 1040-NR typically required.

Tax Treaties

US has income tax treaties with many countries to avoid double taxation. May reduce/eliminate US tax on certain US-source income (dividends, interest, royalties, pensions). Saving clause generally prevents US citizens/residents from using treaty to avoid US tax on US-source income. Treaty-based return positions reported on Form 8833.

Key Decision Factors