Who Has to Pay Federal Income Tax? Thresholds and Dependents

You have to file a federal income tax return if your gross income for 2025 reaches the threshold set for your filing status and age, if you had net self-employment earnings of $400 or more, or if one of a handful of special situations applies. For a single filer under 65, the 2025 threshold is $15,750. For a married couple filing jointly and both under 65, it’s $31,500. Those are the numbers most people who ask who has to file federal income taxes are actually looking for, but the full answer depends on a few more variables, and in some cases you should file even when you aren’t required to.

Income Thresholds by Filing Status and Age

Your filing status and age together set the income level at which the IRS expects a return. Gross income for this purpose means all money, goods, property, and services you receive that aren’t tax-exempt: wages, interest, dividends, rental income, gains from selling property, and more.¹

Under Age 65

Single: $15,750 or more
Married filing jointly, both spouses under 65: $31,500 or more
Head of household: $23,625 or more
Qualifying surviving spouse: $31,500 or more
Married filing separately: $5 or more

Age 65 or Older

Single: $17,750 or more
Married filing jointly, one spouse 65 or older: $33,100 or more
Married filing jointly, both spouses 65 or older: $34,700 or more
Head of household: $25,625 or more
Qualifying surviving spouse: $33,100 or more
Married filing separately: $5 or more

The thresholds are tied to the standard deduction, which is why they climb once you reach 65: people 65 and up get a larger standard deduction.¹ The IRS treats you as 65 at the end of the tax year if your 65th birthday falls on or before January 1 of the following year.

The $5 figure for married filing separately isn’t a typo. It’s set that low on purpose, to keep couples from splitting income across separate returns to manipulate brackets while one spouse itemizes.¹ Qualifying surviving spouse status, meanwhile, lets you use the joint thresholds for up to two years after your spouse’s death if you have a dependent child living with you.

Self-Employment: The $400 Rule

If you work as an independent contractor, freelancer, or small business owner, the ordinary thresholds don’t protect you. You must file once your net self-employment earnings reach $400, no matter how far below the W-2 thresholds your total income sits.² Net earnings means total business income minus ordinary business expenses, reported on Schedule C.

The reason is self-employment tax. It covers the Social Security and Medicare contributions an employer would normally split with you, at a combined rate of 15.3%: 12.4% for Social Security and 2.9% for Medicare.³ You calculate it on Schedule SE and attach it to Form 1040. Even if deductions wipe out your income tax, self-employment tax still applies once you cross the $400 mark.

Filing Rules for Dependents

If someone else claims you as a dependent, the ordinary thresholds don’t apply to you. Dependents follow a separate table based on the type and amount of income received, and the IRS splits that income into earned (wages, tips, salary) and unearned (interest, dividends, capital gains). For 2025, a single dependent under 65 who is not blind must file if any of the following is true:¹

Unearned income is more than $1,350.
Earned income is more than $15,750.
Combined gross income exceeds the larger of $1,350, or your earned income (up to $15,300) plus $450.

Dependents who are 65 or older or blind get higher thresholds. A married dependent must also file if their gross income is $5 or more and their spouse files separately with itemized deductions, the same low-threshold rule that governs married filing separately generally.

These smaller thresholds keep high-income parents from shifting investment assets to children to reach lower brackets. In some cases parents can skip a separate return for their child by reporting the child’s investment income on their own return with Form 8814. The election is available only when the child’s income comes solely from interest and dividends (including capital gain distributions), the child’s gross income is under $13,500 for 2025, and several other conditions are met.⁴

If You Aren’t a U.S. Citizen

U.S. citizens file on their worldwide income no matter where they live, even if they reside abroad full-time and pay taxes to another country. For foreign nationals, everything depends on residency status.

The IRS decides whether you count as a resident alien through the Substantial Presence Test. You meet it if you were physically present in the United States for at least 31 days during the current year and at least 183 days over a three-year period, calculated as all days in the current year, one-third of the days in the prior year, and one-sixth of the days in the year before that.⁵ Meet the test and you’re taxed like a U.S. citizen on your worldwide income, using the thresholds above.

Nonresident aliens who don’t meet the test but earn U.S.-source income, such as wages from a U.S. employer or investment income from U.S. assets, generally must file Form 1040-NR.⁶ Nonresident aliens engaged in a U.S. trade or business must file even if they had no U.S.-sourced income or their income is exempt under a tax treaty.

Other Situations That Trigger a Return

A few financial events force a filing even when your income sits below the normal thresholds. In each case, the IRS can only track a particular tax or credit through a filed return.

You owe Alternative Minimum Tax, the parallel calculation designed to make sure higher-income taxpayers pay at least a minimum amount.
You took a distribution from a Health Savings Account or Archer MSA, which the IRS needs to reconcile against qualifying medical expenses.
You received advance payments of the Premium Tax Credit toward Marketplace health coverage. You must file Form 8962 to reconcile the advance payments against the credit your final income actually supports. Skipping the reconciliation can cost you eligibility for future advance payments.⁷
You paid a nanny, housekeeper, or other household worker enough to owe household employment taxes, which get reported on your return.
You earned $108.28 or more from a church or church-controlled organization that opted out of paying the employer share of Social Security and Medicare taxes. You owe self-employment tax on those wages and report it on Schedule SE.⁸

When You Should File Even If You Don’t Have To

Falling below the threshold doesn’t always mean filing is a waste of time. The IRS identifies three situations where a voluntary return can put money back in your pocket:⁹

Federal income tax was withheld from your paycheck. The only way to get it back is to file and claim a refund.
You qualify for a refundable credit. The Earned Income Tax Credit and the refundable portion of the Child Tax Credit can pay you even when you owe zero tax, but only if you file.
You made estimated tax payments and overpaid during the year.

The stakes on the credits can be substantial. The Earned Income Tax Credit for 2025 is worth up to $8,231 for a family with three or more qualifying children. The Child Tax Credit is worth up to $2,200 per child under 17, with up to $1,700 of that refundable. Both credits phase in starting at $2,500 of earned income. If you qualify and don’t file, that money stays with the Treasury.

Deadlines and Penalties If You Miss

The deadline to file a 2025 return is April 15, 2026. If you need more time, Form 4868 buys an automatic six-month extension to October 15, 2026, but only for filing the paperwork.¹⁰ Any tax you owe is still due on April 15.

If you were required to file, missing the deadline without an extension triggers a failure-to-file penalty of 5% of the unpaid tax for each month or partial month the return is late, capped at 25%.¹¹ The penalty is calculated against unpaid tax, so a late return with a refund coming to you carries no penalty. It just delays your money.

A separate failure-to-pay penalty applies if you file on time but don’t pay what you owe. It runs at 0.5% of the unpaid balance per month, also capped at 25%, and drops to 0.25% per month once you’re on an approved installment agreement.¹² When both penalties apply in the same month, the filing penalty is reduced by the payment penalty so they don’t fully stack. Interest runs on top of both.

1
Internal Revenue Service. Publication 501 (2025), Dependents, Standard Deduction, and Filing Information
2
Internal Revenue Service. Topic No. 554, Self-Employment Tax
3
Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
4
Internal Revenue Service. 2025 Instructions for Form 8814
5
Internal Revenue Service. Substantial Presence Test
6
Internal Revenue Service. 2025 Instructions for Form 1040-NR, U.S. Nonresident Alien Income Tax Return
7
Internal Revenue Service. Instructions for Form 8962 (2025)
8
Internal Revenue Service. Publication 517 (2025), Social Security and Other Information for Members of the Clergy and Religious Workers
9
Internal Revenue Service. Check If You Need to File a Tax Return
10
Internal Revenue Service. When to File
11
Internal Revenue Service. Failure to File Penalty
12
Internal Revenue Service. Failure to Pay Penalty