26 U.S.C. § 6012: Persons Required to File a Return

You are required to file a federal income tax return if your gross income for the year meets the threshold set for your filing status and age, or if one of a handful of special situations applies to you regardless of income. For tax year 2025, that baseline threshold is $15,750 for a single person under 65.¹ Below the threshold and outside the special triggers, filing is optional — but often still worth doing to collect a refund. The rules sit in 26 U.S.C. § 6012.²

The Gross Income Test

Your filing threshold equals the standard deduction for your filing status, plus the extra standard deduction if you are 65 or older. Gross income means everything you received during the year that is not specifically tax-exempt: wages, business revenue, investment returns, rental income. Tax-exempt items such as municipal bond interest do not count toward the threshold. If your gross income meets or exceeds the number below, you must file.¹

For tax year 2025, the thresholds are:³

Single, under 65: $15,750
Single, 65 or older: $17,750
Head of household, under 65: $23,625
Head of household, 65 or older: $25,625
Married filing jointly, both under 65: $31,500
Married filing jointly, one spouse 65 or older: $33,100
Married filing jointly, both 65 or older: $34,700
Married filing separately, any age: $5
Qualifying surviving spouse, under 65: $31,500
Qualifying surviving spouse, 65 or older: $33,100

The $5 threshold for married filing separately is not a typo. Any married person who elects to file separately effectively must file.

The Age 65 Adjustment

You qualify for the additional standard deduction, and the higher filing threshold that comes with it, if you turned 65 before January 2, 2026. The additional amount for 2025 is $2,000 for single or head of household filers, and $1,600 for married filers or a qualifying surviving spouse.⁴ When both spouses on a joint return are 65 or older, they each get $1,600, which is why the joint threshold reaches $34,700.

Head of Household and Qualifying Surviving Spouse

Head of household is available to unmarried taxpayers who paid more than half the cost of maintaining a home for a qualifying person such as a child or dependent parent. The higher standard deduction produces a meaningfully higher filing threshold than single status.

If your spouse died in 2024 or 2025 and you have a dependent child, you can use qualifying surviving spouse status for up to two years after the year of death. The threshold matches married filing jointly.¹

Situations That Require You to File Regardless of Income

Several triggers force a return even when your gross income sits below the threshold.

Self-Employment Earnings of $400 or More

If your net self-employment earnings reach $400, you must file. This applies regardless of filing status and regardless of whether you would otherwise owe income tax.⁵ The IRS needs the return to collect Social Security and Medicare taxes, which for self-employed workers run at a combined 15.3% rate covering both the employee and employer portions.⁶ Net earnings means business revenue minus deductible business expenses, reported on Schedule C, with the self-employment tax calculated on Schedule SE.

Advance Premium Tax Credits

If the health insurance marketplace paid Advance Premium Tax Credits toward your coverage, you must file to reconcile those payments, even if your income falls below the normal threshold.⁷ Reconciliation happens on Form 8962, attached to your return.⁸ Skipping this step can force repayment of the advance credits and cut off future advance payments until you show proof of reconciliation.

Social Security With Other Income

Social Security benefits are generally excluded from gross income for the filing test unless your combined income crosses a threshold. Combined income means half of your Social Security benefits plus all other income, including tax-exempt interest. When that total exceeds $25,000 for single filers or $32,000 for married couples filing jointly, benefits become partially taxable and count toward the filing threshold.⁹ Different rule if you are married filing separately and lived with your spouse at any point during the year: benefits are always included in gross income regardless of amount.¹

Dependents

If someone else claims you as a dependent, your thresholds change. Income splits into two categories, earned (wages, tips, salary) and unearned (interest, dividends, capital gains), with separate triggers for each. For 2025, a single dependent under 65 must file if any of the following applies:¹

Unearned income more than $1,350
Earned income more than $15,750
Both types, where gross income exceeds the greater of $1,350 or earned income (up to $15,300) plus $450

A single dependent who is 65 or older must file if unearned income exceeds $3,350 or earned income exceeds $17,750. Married dependents have their own set of thresholds. Dependents also must file if they owe any special taxes, such as the additional tax on an early retirement account distribution, regardless of income level.

U.S. Citizens and Residents Abroad

The United States taxes citizens and resident aliens on worldwide income, wherever earned. If you are a U.S. citizen working overseas, you must file whenever your global gross income meets the standard threshold for your status.¹⁰

The Foreign Earned Income Exclusion lets qualifying taxpayers exclude up to $130,000 of foreign earnings for 2025 ($132,900 for 2026).¹¹ Claiming the exclusion does not remove the filing obligation. You still submit a return with Form 2555 attached so the IRS can verify eligibility. Only if your gross income before the exclusion sits below the filing threshold are you off the hook.

Filing a Return for Someone Who Died

When a taxpayer dies, someone still files their final return if income met the regular threshold. The return covers January 1 through the date of death and is due by the normal April 15 deadline the following year.¹²

Who signs depends on the situation. A personal representative named in the will or appointed by a court signs the return. Without a representative, a surviving spouse filing a joint return signs and writes “filing as surviving spouse” in the signature area. If neither exists, whoever is managing the deceased person’s property signs as “personal representative.”¹³ Write “DECEASED,” the person’s name, and date of death across the top. A joint return with the surviving spouse is allowed for the year of death, but not if the surviving spouse remarried before year-end.¹² File even when not required if the deceased had withholding or estimated payments to be refunded.

When Filing Is Optional but Still Worth It

Falling below the filing threshold does not mean you should skip the return. If your employer withheld federal income tax and you earned less than the threshold, filing is the only way to get that money back. Several refundable credits can also pay out even when you owe no tax:¹⁴

Earned Income Tax Credit, worth up to $8,046 for a family with three or more children in 2025, with income limits ranging from $19,104 (single, no children) to $68,675 (married filing jointly, three or more children).¹⁵
Additional Child Tax Credit, refundable up to $1,700 per qualifying child for 2025.
American Opportunity Tax Credit, refundable up to $1,000.

The IRS estimates that billions in EITC go unclaimed each year because eligible workers simply do not file. One hard deadline governs any refund claim: you have three years from the return’s original due date to claim it. Miss that window and the money is gone.¹⁶ For a 2025 return normally due April 15, 2026, you must file by April 15, 2029.

What Happens If You Should Have Filed and Didn’t

The failure-to-file penalty runs 5% of unpaid tax for each month or partial month the return is late, capped at 25%.¹⁷ The failure-to-pay penalty, by contrast, is 0.5% per month. Missing paperwork is penalized ten times more aggressively than missing payments.

If your return runs more than 60 days late, the minimum penalty jumps to the lesser of $525 or 100% of the tax owed.¹⁷ Interest compounds daily on top, at the federal short-term rate plus three percentage points.

Willful failure to file crosses into criminal territory. It is a misdemeanor under 26 U.S.C. § 7203, carrying up to one year in prison and a fine of up to $25,000; if the IRS can show non-filing was part of a scheme to evade taxes, felony charges are possible.¹⁸

One point worth knowing if you are years behind: if you never file a required return, there is no statute of limitations on assessment. The IRS can pursue the tax, penalties, and interest indefinitely. Filing, even late, starts the normal three-year assessment clock. Late filing is always better than no filing.

1
Internal Revenue Service. Publication 501, Dependents, Standard Deduction, and Filing Information
2
Office of the Law Revision Counsel. 26 USC 6012 – Persons Required to Make Returns of Income
3
Internal Revenue Service. Publication 554, Tax Guide for Seniors
4
Internal Revenue Service. Topic No. 551, Standard Deduction
5
Internal Revenue Service. Self-Employed Individuals Tax Center
6
Internal Revenue Service. Topic No. 554, Self-Employment Tax
7
Internal Revenue Service. Reconciling Your Advance Payments of the Premium Tax Credit
8
Internal Revenue Service. 2025 Instructions for Form 8962 Premium Tax Credit
9
Internal Revenue Service. Social Security Income
10
Internal Revenue Service. Foreign Earned Income Exclusion
11
Internal Revenue Service. Figuring the Foreign Earned Income Exclusion
12
Internal Revenue Service. Publication 559, Survivors, Executors, and Administrators
13
Internal Revenue Service. Filing a Final Federal Tax Return for Someone Who Has Died
14
Internal Revenue Service. Refundable Tax Credits
15
Internal Revenue Service. Earned Income and Earned Income Tax Credit Tables
16
Internal Revenue Service. Time You Can Claim a Credit or Refund
17
Internal Revenue Service. Failure to File Penalty
18
Office of the Law Revision Counsel. 26 USC 7203 – Willful Failure to File Return, Supply Information, or Pay Tax