Single Filing Status

Single is the federal filing status for an individual who is not married at the end of the tax year and does not qualify for head of household or for qualifying surviving spouse. Publication 501 states it as a residual: "Your filing status is single if you are considered unmarried and you don't qualify for another filing status." The naming is worth a moment, because the short label hides the rule. Section 1(c) of the Internal Revenue Code, and the annual revenue procedure that publishes the year's rate tables, both describe this class as "Unmarried Individuals (other than Surviving Spouses and Heads of Households)." That longer name is the definition. Form 1040's one-word checkbox is the same status under a shorter label, and both are official wording.

Being unmarried is not sufficient, and the order of testing is written into the statute. Section 2(a) defines surviving spouse. Section 2(b) then defines head of household and grants it only to an individual who "is not married at the close of his taxable year, is not a surviving spouse," and meets a household test. So the two better unmarried statuses are tested first by the structure of the Code itself, not merely as a matter of good practice, and single is what remains when neither is available. Neither of the other two is elective. Each is a factual test that either is met or is not, which means an unmarried taxpayer cannot choose single for simplicity if a better status genuinely applies.

When you count as unmarried. Section 7703(a)(1) determines marital status as of the close of the taxable year, so a divorce that becomes final on the last day of December makes someone unmarried for the whole year, and a wedding on the same date makes someone married for the whole year. Section 7703(a)(2) adds that an individual legally separated from their spouse under a decree of divorce or of separate maintenance is not considered married. A separation agreement without a decree does not have that effect. The one departure from the close-of-year rule is a death: where a spouse dies during the year, status is fixed at the date of death, which is what preserves a joint return for that year and means a survivor is generally not single for the year the death occurred.

Publication 501 turns the married side into four tests, and meeting any one of them is enough. You are considered married for the whole year if, on its last day, you are married and living together; are living together in a common law marriage recognized either in the state where you now live or in the state where that marriage began; are married and living apart without a decree of divorce or separate maintenance; or are separated under an interlocutory, meaning not final, decree of divorce. That last test is the one that catches people out. A divorce can be granted, the parties can have separate homes, and both can still be married for the entire year until the decree is final. Whether a marriage or a legal separation exists at all is a question of state law, which the federal rules take as given rather than decide.

What counts as a marriage is settled by where it was celebrated, not by where you now live. A marriage of two individuals is recognized for federal tax purposes if the state or territory in which it was entered into recognizes it, whatever the couple's later residence, and a relationship denominated as marriage under the law of a foreign jurisdiction or an American Indian tribe is recognized if it would be a marriage under the law of at least one state or territory. Same-sex spouses have been married for every federal tax purpose since Revenue Ruling 2013-17. The line the rule draws is about the label rather than the substance of the relationship: a registered domestic partnership, a civil union, or a similar status that the enacting state does not itself denominate a marriage is not a marriage for federal tax purposes. Two partners in that position each file as unmarried, however long the relationship has run and however completely state law treats them as spouses.

An annulment reaches backward; a divorce does not. A court decree of annulment holds that no valid marriage ever existed, so the individual is considered unmarried even for years in which joint returns were actually filed, and Publication 501 directs amended returns on Form 1040-X claiming single or head of household for every affected year still open. The window is the ordinary refund window rather than a special one: generally three years from the date the original return was filed, including extensions, or two years from the date the tax was paid, whichever is later. Running the other way, the rules refuse to let the calendar be gamed. A couple who divorce for the sole purpose of filing as unmarried, intending to and in fact remarrying each other the following year, must file as married in both years.

The bereavement sequence runs in three steps, and single is the last one. The year of death is generally a joint return. For the two years following, qualifying surviving spouse may be available to a survivor who has not remarried, who paid more than half the cost of keeping up a home, and whose child or stepchild lived in that home. After those two years, head of household may be available if a qualifying person is still in the household, and single is what applies if none of that is true. Publication 501's own Single section reflects the sequence: it notes that a survivor's status may be single, and in the next breath sends the reader to check head of household and qualifying surviving spouse first.

Remarrying in the year of a death rearranges both returns. A survivor who remarries before the end of that year files jointly with the new spouse, and the deceased spouse's own final return then carries the status married filing separately. None of that is elective, and it is easy to miss, because the decedent's return is usually prepared by someone thinking about the survivor's filing rather than the decedent's.

Single sits beside married filing separately, and the pairing explains both. Each is a residual status, so the distinction between them is not that one is elective, it is which marital branch the residual sits in. Single is what applies to someone treated as unmarried with nothing better available. Married filing separately is what applies to someone who is married and has not made the joint election. The rate tables reflect that closeness, and the statute shows exactly why. In its own base dollars the separate-return table is precisely half the joint table at every boundary, and the single table is half of it at every boundary but one. So the two coincide almost everywhere: the top of the 22% band is $82,500 on each against $165,000 joint, and the top of the 32% band is $200,000 against $400,000. The exception is the last boundary. The 37% rate begins at $300,000 for a separate filer, exactly half the $600,000 joint figure, and at $500,000 for a single filer, which is where the two tables part company. Everything below that boundary stays identical from year to year as well, because both statuses have their inflation adjustments rounded in the same $25 steps, while the gap at the top persists in roughly the same proportion. The published dollar boundaries change annually and are at IRS.gov.

What single does not cost. It is easy to read "not married" as a penalty status, and it is not one. A single filer keeps the education credits, the student loan interest deduction, the full capital loss allowance and the ordinary credit phase-out ranges. Married filing separately is the status that strips or halves that list, which is why a married person living apart with a child in the home is usually better served by testing head of household than by accepting a separate return.

Two situations look like single and are not. A person married to a nonresident alien is still married. Where the couple make no election to treat the nonresident spouse as a resident, Publication 501 considers the taxpayer unmarried for head of household purposes only, and even then the nonresident spouse is not a qualifying person, so head of household needs some other qualifying person in the household. Absent one, the return is married filing separately. The living-apart rule works the same way: a married person who lived apart from their spouse for the last six months of the year and maintains a home for their own child may be considered unmarried, but what that opens is head of household, not single. Publication 501 states the limit directly, warning that a taxpayer may be considered unmarried for head of household purposes and not for other purposes such as the earned income credit, because different tests apply to different benefits.

The current year's figures, with five years of history behind them. The table below is generated from this site's single source of truth for year-indexed amounts, so the 2026 row moves when the annual figures do. Read every rate column as the top of that band. Each figure is the "not over" amount the IRS publishes, the boundary dollar itself is taxed at the lower rate, and the next rate reaches only the excess above it. So a single filer with taxable income of exactly $12,400 is taxed entirely at 10 percent, and one at $50,400 pays 10 percent on the first $12,400 and 12 percent on the rest. Anything above the last column is taxed at 37 percent. The 2021 through 2025 rows are history and will not change.

One step in that table deserves explaining rather than being read as a misprint. Between 2025 and 2026 the top of the 10 percent band and the top of the 12 percent band rose by roughly 4 percent, while the four boundaries above them rose by roughly 2.3 percent. The cause is statutory. Section 70101(b) of the One Big Beautiful Bill Act (Public Law 119-21) narrowed the "calendar year 2017" base-year substitution in section 1(j)(3)(B)(i) so that it reaches only the upper boundaries, which leaves the two lowest ones on the default 2016 base and therefore one additional year of indexing. It is a one-time change in level, not the start of a trend in proportional terms. The 2025 standard deduction row is likewise the raised amount rather than the figure first published for 2025: the same Act increased it, and the following year's revenue procedure formally struck the superseded paragraph from its predecessor, so the lower number still circulating in older write-ups was never operative for anyone.

The determination runs in a fixed order. First fix marital status as of the last day of the tax year, remembering that a spouse's death fixes it at the date of death instead and that a decree of divorce or separate maintenance means not married. If the answer is married, the questions are whether to make the joint election and whether the living-apart route to head of household is available. If the answer is unmarried, test qualifying surviving spouse first, then head of household. Single is what applies when neither fits.

A hypothetical example of the sequence rather than of arithmetic, because the status itself involves no calculation. Mara's husband dies in the first year. That year she files a joint return, since marital status is fixed at the date of death. In the second and third years her daughter lives at home and Mara pays the household costs, so she uses qualifying surviving spouse and the joint rate table. In the fourth year her daughter has moved out and no one else in the household qualifies, so nothing better than single is available and single is what she files. Three statuses in four years, none of them chosen, each one the result of a test applied to that year's facts.

One more hypothetical, this time where the intuitive answer is wrong. Priya separates from her husband in March and files a petition; the court grants a decree in October, but it is interlocutory and the final judgment is not entered until February. Because an interlocutory decree leaves the parties married, Priya is married for the whole of the first year, so her options are married filing separately or, because her spouse was not a member of her household for the last six months and her home was her son's main home, head of household. Single does not become available to her until the following year. The same shape recurs for someone whose spouse is a nonresident alien: no amount of living apart makes that person single, because the marriage itself still exists.

Where the choice of status does show up in dollars, the comparison worth knowing is against married filing separately rather than against a joint return. Both carry the same standard deduction, and in the statute's base dollars every bracket boundary is identical between them until the last one, where the 37% rate starts at $500,000 for a single filer and $300,000 for a separate filer. For almost every taxpayer, then, the two tables produce the same tax on the same taxable income, and what actually separates the two statuses is the long list of credits and deductions a separate return gives up.

What the status offers

• Every credit and deduction remains available on its ordinary terms, which is not true of a married person filing separately.
• No coordination with anyone. One return, one signature, and no exposure to another person's reporting.
• Simple to determine once marital status is settled, because it requires no household test, no dependent and no cost calculation.

Limits and cautions

• It is the weakest of the unmarried statuses, so settling for it without testing head of household and qualifying surviving spouse can cost real money.
• Its standard deduction and its two lowest rate bands are the narrowest of the four individual tables, tied with married filing separately, and income-tested limits set for a single filer are generally the lowest as well.
• A survivor who defaults to it in the year of a spouse's death, or in the two years after, is likely using the wrong status for that year.
• It says nothing about household economics. Someone supporting relatives who do not meet a qualifying-person test files exactly the same return as someone supporting nobody.