The short answer: with tax filing status explained in one paragraph, a US federal return uses one of five statuses: single, married filing jointly, married filing separately, head of household, or qualifying surviving spouse. Which ones are available depends mainly on marital status on the last day of the tax year, plus whether the filer kept up a home for a qualifying person. When more than one status fits, IRS Publication 501 says to choose the one that gives the lowest tax. The status then sets the standard deduction, the bracket thresholds and eligibility for several credits.
Filing status is the first box on Form 1040, and it quietly drives most of what follows. This article sets out each status, the order in which the Internal Revenue Service's rules narrow the options, and the few decisions that cannot be undone later.
Rules and figures in this article were checked on September 25, 2026, against IRS pages for tax year 2025. Amounts tied to filing status change every year.
The five statuses at a glance
The IRS filing status page (last updated June 29, 2026, read September 25, 2026) summarizes the five like this:
| Status | IRS summary |
|---|---|
| Single | "if you're unmarried, divorced or legally separated" |
| Married filing jointly | "if you're married or if your spouse passed away during the year" |
| Married filing separately | "if you're married and don't want to file jointly or find that filing separately lowers your tax" |
| Head of household | "if you're single and you paid more than half of your living expenses for yourself and a qualifying dependent" |
| Qualifying surviving spouse | "if your spouse died during the past 2 years and you have a dependent child" |
Those one-line summaries are starting points. The full conditions, which decide the edge cases, are in IRS Publication 501 (2025), read September 25, 2026.
Step one: marital status on December 31
The single most important fact is where the filer stood on the last day of the year. Publication 501 states that a person is "considered unmarried for the whole year if, on the last day of your tax year, you are either: Unmarried, or Legally separated from your spouse under a divorce or separate maintenance decree."
This produces results that surprise people:
- A couple who married on December 30 is treated as married for the whole year.
- A person whose divorce became final on December 30 is treated as unmarried for the whole year.
- A person whose spouse died during the year is "considered married for the whole year for filing status purposes," per Publication 501.
State relationship labels do not always carry over. Publication 501 states that people in "a registered domestic partnership, civil union, or other similar relationship that isn't denominated as a marriage" are not considered married for federal tax purposes.
Tax filing status explained, one status at a time
Single
Single is the default for someone unmarried, divorced or legally separated under a decree on December 31 who does not qualify for head of household or qualifying surviving spouse. It has its own bracket thresholds and standard deduction. For tax year 2025, the IRS lists the single standard deduction at $15,750.
Married filing jointly
Spouses combine income, deductions and credits on one return. For tax year 2025, the IRS lists the joint standard deduction at $31,500. The IRS filing status page notes that "most couples save money by filing jointly," though that is a general observation, not a guarantee for every couple.
A joint return carries a responsibility that is easy to overlook. Publication 501 states: "Both of you may be held responsible, jointly and individually, for the tax and any interest or penalty due on your joint return," and "one spouse may be held responsible for all the tax due even if all the income was earned by the other spouse."
Married filing separately
Each spouse files a return reporting their own income and deductions. Publication 501 lists special rules that apply, including that "your tax rate is generally higher than on a joint return," that the credit for child and dependent care expenses generally cannot be taken, and that the earned income credit cannot be taken unless the filer has a qualifying child. Publication 501 also lists education credits among the items not available on a separate return, and it repeats the rule that if one spouse itemizes deductions, the other cannot claim the standard deduction.
Couples sometimes still choose it, for example when each spouse wants to be responsible only for their own return, which is the other side of the joint liability rule above.
Head of household
Head of household is for an unmarried person, or one "considered unmarried," who paid more than half the cost of keeping up a home and had a qualifying person live there for more than half the year. A dependent parent is a notable exception: the parent does not have to live with the filer. Publication 501 notes that a head of household's "tax rate will usually be lower than the rates for single or married filing separately" and that the filer "will also receive a higher standard deduction." For tax year 2025, the IRS lists that deduction at $23,625.
"Considered unmarried" is the path for some people who are still legally married. Among the conditions in Publication 501: "Your spouse didn't live in your home during the last 6 months of the tax year." The other conditions, such as filing a separate return and keeping up the home for a qualifying child, must also be met.
The costs of keeping up a home, per the worksheet in Publication 501, include rent, mortgage interest, property taxes, utilities, repairs and maintenance, property insurance, food eaten in the home and other household expenses.
Qualifying surviving spouse
Publication 501 states that a widowed filer "may be eligible to use qualifying surviving spouse as your filing status for 2 years following the year your spouse died," with a dependent child required. The status "entitles you to use joint return tax rates and the highest standard deduction amount (if you don't itemize deductions)."
In the year of death itself, the surviving spouse is generally still able to file jointly, as noted above. So the sequence for a widowed parent is often: joint for the year of death, then qualifying surviving spouse for up to two years, then head of household or single. A death also triggers non-tax paperwork, including claims under policies such as life insurance, covered in how a life insurance beneficiary designation works.
The order used to narrow it down
Put together, the rules work like a decision path. This is a summary of the logic, not a substitute for Publication 501 or the IRS Interactive Tax Assistant:
| Question | If yes | If no |
|---|---|---|
| Married on December 31 (or spouse died during the year)? | Joint or separate are available; check "considered unmarried" for head of household | Go to the next question |
| Spouse died in one of the two prior years, with a dependent child at home? | Qualifying surviving spouse may apply | Go to the next question |
| Paid more than half the cost of a home for a qualifying person? | Head of household may apply | Single |
When more than one box could fit, Publication 501 is explicit: "If more than one filing status applies to you, choose the one that will give you the lowest tax." That is a comparison of results, which is why preparers often figure a married couple's return both ways.
What filing status changes on the return
Filing status is not a label; it is an input. It changes:
- The standard deduction. For tax year 2025, the IRS lists $15,750 for single or married filing separately, $31,500 for married filing jointly and $23,625 for head of household.
- The bracket thresholds. Each status has its own dollar edges for the same seven rates.
- Credit eligibility and phaseouts. Several credits are limited or unavailable on a separate return, as listed above.
- Income limits outside the Form 1040 math. Eligibility rules for some retirement accounts, such as Roth IRA contributions, are set by filing status, which matters when comparing the main types of retirement accounts.
Life events that change status often change other things at the same time. Divorce, for instance, can end a spouse's coverage under an employer health plan, which is one of the situations covered in how COBRA continuation works between plans.
The door that only opens one way
Publication 501 describes an asymmetry worth knowing before filing. "You can change your filing status from a separate return to a joint return by filing an amended return." But "once you file a joint return, you can't choose to file separate returns for that year after the due date."
In practice, that makes the joint choice the harder one to reverse. Couples with concerns about the other spouse's return, or about joint liability, face a decision here that a tax professional or attorney can help them weigh with the specifics in hand.
What this article cannot decide
This is general information about how federal filing status is determined. Which status applies to a household, and which gives the lowest tax when several fit, depends on facts this article cannot see: dates, living arrangements, who paid for the home and who qualifies as a dependent. A tax professional, such as a CPA or enrolled agent, or an IRS-certified volunteer preparer can settle it. They will need marriage, divorce or separation dates, the relevant decree if any, records of household costs and the dependents' details. The IRS Interactive Tax Assistant also walks through the questions.
Frequently asked questions
What determines filing status for the whole year?
Marital status on the last day of the tax year. Publication 501 treats a person who is unmarried or legally separated under a decree on that day as unmarried for the whole year, and a person whose spouse died during the year as married for the whole year.
Can a married person file as head of household?
Sometimes. A married person who meets the "considered unmarried" conditions in Publication 501, including that the spouse did not live in the home during the last six months of the year, may qualify.
What if more than one filing status applies?
Publication 501 says to choose the one that gives the lowest tax.
How long can someone use qualifying surviving spouse status?
For up to two years following the year the spouse died, with a dependent child and the other conditions in Publication 501 met.
Can a joint return be changed to separate returns later?
Not after the due date. Publication 501 states that once a joint return is filed, separate returns cannot be chosen for that year after the due date, while a switch from separate to joint can be made with an amended return.
