Is Filing Taxes Mandatory? Income Thresholds and Penalties

Yes, filing a federal tax return is mandatory once your gross income reaches the threshold set for your filing status and age, and it is also mandatory in a handful of specific situations regardless of how much you earned. For the 2026 tax year, a single filer under 65 must file at $16,100 of gross income; a married couple filing jointly, both under 65, must file at $32,200.¹ The requirement itself comes from federal statute, not IRS discretion.²

2026 Income Thresholds That Require a Return

Gross income means almost everything of value you received during the year: wages, tips, self-employment income, interest, dividends, capital gains, and most other cash or property. If your total hits the number for your status, you must file.

For 2026, the filing thresholds if you are under 65 are:

Single: $16,100
Married filing jointly, both under 65: $32,200
Married filing jointly, one spouse 65 or older: $33,850
Head of household: $24,150
Qualifying surviving spouse: $32,200
Married filing separately: $5, at any age

If you are 65 or older, the threshold rises. A single filer 65 or older must file at $18,150, and a married couple filing jointly with both spouses 65 or older must file at $35,500.¹

The $5 married-filing-separately threshold looks like a typo but is deliberate. The tax code sets it that low so a spouse cannot avoid filing while the other spouse itemizes deductions on their own return.² If you file separately and have essentially any income, you file.

The $400 Self-Employment Rule

Self-employment income follows a much lower and separate rule. If your net earnings from self-employment reach $400 for the year, you must file, even if your total income is well below the standard threshold for your filing status.³

Net earnings means your business income minus allowable expenses. The reason the threshold is so low is self-employment tax, which covers the Social Security and Medicare contributions that an employer would otherwise split with you.⁴ The combined rate is 15.3%: 12.4% for Social Security and 2.9% for Medicare. A few hundred dollars of profit from a side gig can be enough to trigger a filing requirement.

Situations That Require Filing No Matter What You Earned

Several events create a filing obligation on their own, independent of income thresholds.

Health Savings Accounts and Marketplace Coverage

If your Health Savings Account or Archer MSA received contributions or made distributions during the year, you must file a return and attach Form 8889, even if you have no taxable income.⁵ If you received advance payments of the Premium Tax Credit to lower your Marketplace health insurance premiums, you must file to reconcile those advance payments against your actual income for the year.⁶ Skipping the reconciliation can cost you the subsidy in future years.

Early Retirement Account Withdrawals

Pulling money out of a traditional IRA, 401(k), or other qualified plan before age 59½ generally triggers a 10% additional tax on top of regular income tax.⁷ You must file to report that tax even if the withdrawal is your only income for the year. Exceptions exist for certain medical expenses, a first home purchase, and substantially equal periodic payments, among others, but you still need a return to claim the exception.

Tips, Household Employees, and AMT

You also must file if you owe the alternative minimum tax, if you had unreported tip income of $20 or more in any single month, or if you owe household employment taxes for a nanny, housekeeper, or other domestic worker.⁸

Social Security Benefits

Social Security by itself does not usually require a return, but it can. If your combined income (adjusted gross income, tax-exempt interest, and half of your benefits) exceeds $25,000 for a single filer or $32,000 for a married couple filing jointly, part of your benefits becomes taxable and a filing requirement can follow.⁹

When Filing Is Optional but Still Worth It

Being below the threshold does not always mean you should skip the return. Filing is often how you get money back.

If your employer withheld federal income tax from your paychecks and your total income is under the threshold, the only way to recover that withholding is to file.¹⁰ Refundable credits can also pay you cash even when you owe no tax:

Earned Income Tax Credit worth up to $8,046 for a worker with three or more qualifying children under the 2025 figures; single filers with no children earning under $19,104 can qualify for a smaller amount.¹¹
Child Tax Credit of $2,200 per qualifying child for 2025 under the One Big Beautiful Bill Act, with inflation adjustments starting in 2026 and a portion refundable.
American Opportunity Tax Credit, up to $1,000 of which is refundable for eligible students or their parents.¹²

Filing also starts the audit clock. If you never file, there is no statute of limitations and the IRS can come after you for that year at any time.¹³ Once a return is filed, the IRS generally has three years to question it.

Penalties If You Were Required to File and Didn’t

Miss a required filing and the cost adds up quickly.

Failure-to-File Penalty

The penalty for filing late is 5% of your unpaid tax for each month or part of a month the return is overdue, up to 25%.¹⁴ If you file more than 60 days late, a minimum penalty applies: the lesser of $525 or 100% of the tax owed.¹⁵

Failure-to-Pay Penalty and Interest

A separate penalty of 0.5% per month applies to unpaid tax, also capped at 25%.¹⁵ When both the failure-to-file and failure-to-pay penalties apply in the same month, the combined rate is capped at 5% rather than 5.5%. Interest runs on top of the penalties at the federal short-term rate plus 3%, compounding daily from the original due date.

Criminal Exposure

Willfully refusing to file when required is a federal misdemeanor. A conviction can carry a fine of up to $25,000, up to one year in prison, or both, plus the costs of prosecution.¹⁶ Criminal prosecution is uncommon and typically involves deliberate evasion across multiple years, but the statute is on the books.

State Returns Are a Separate Question

Meeting or missing the federal threshold says nothing about your state obligation. Most states have their own income tax with their own filing rules, some triggering at any dollar of income and others tracking closer to the federal approach. A few states have no income tax at all. Check your state’s department of revenue or taxation for the rules that apply to you.

1
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill
2
Office of the Law Revision Counsel. 26 USC 6012 – Persons Required to Make Returns of Income
3
eCFR. 26 CFR 1.1402(b)-1 – Self-Employment Income
4
Office of the Law Revision Counsel. 26 USC 1402 – Definitions
5
Internal Revenue Service. Instructions for Form 8889
6
Internal Revenue Service. Reconciling Your Advance Payments of the Premium Tax Credit
7
Office of the Law Revision Counsel. 26 USC 72 – Annuities; Certain Proceeds of Endowment and Life Insurance Contracts
8
Internal Revenue Service. Publication 531, Reporting Tip Income
9
Office of the Law Revision Counsel. 26 USC 86 – Social Security and Tier 1 Railroad Retirement Benefits
10
Internal Revenue Service. Check if You Need to File a Tax Return
11
Internal Revenue Service. Earned Income and Earned Income Tax Credit (EITC) Tables
12
Internal Revenue Service. Refundable Tax Credits
13
Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection
14
Internal Revenue Service. Failure to File Penalty
15
Internal Revenue Service. Topic No. 653, IRS Notices and Bills, Penalties and Interest Charges
16
Office of the Law Revision Counsel. 26 USC 7203 – Willful Failure to File Return, Supply Information, or Pay Tax