Who Must File Form 1040

General Income Thresholds

The IRS sets minimum gross income thresholds each year based on filing status and age. For the 2024 tax year, single filers under 65 generally must file if gross income exceeds $14,600. Married couples filing jointly have a higher threshold of $29,200 when both spouses are under 65, and higher still if one or both are 65 or older. Head of household filers have a threshold of $21,900. These amounts are adjusted annually for inflation and represent the sum of the standard deduction plus any additional standard deduction for age.

Gross income includes all income from any source that isn’t specifically excluded by law — wages, salaries, tips, interest, dividends, capital gains, rental income, alimony received under pre-2019 agreements, business income, and any other earnings. Even income earned outside the United States counts toward these thresholds for citizens and residents.

Self-Employment Income

If you had net self-employment income of $400 or more during the year, you must file a return regardless of whether your total income exceeds the standard filing thresholds. This requirement exists because self-employment tax — the Social Security and Medicare taxes that employers and employees normally split — must be calculated and paid through the tax return. Freelancers, independent contractors, sole proprietors, and gig workers are all subject to this rule. The $400 threshold applies to net earnings after deducting business expenses, not gross receipts.

Dependent Filing Rules

Individuals who can be claimed as dependents on another taxpayer’s return face separate, more complex thresholds. A dependent must file if earned income exceeds the standard deduction amount, or if unearned income (interest, dividends, capital gains) exceeds $1,300, or if the combination of earned and unearned income exceeds certain calculated limits. These rules prevent dependents from sheltering investment income without reporting it.

Special Situations That Require Filing

Several circumstances require filing even when income is below the normal thresholds. You must file if you owe alternative minimum tax, if you owe household employment taxes for domestic workers, if you received Health Savings Account distributions, if you owe taxes on a qualified retirement plan including an IRA, or if you owe Social Security or Medicare tax on tips you didn’t report to your employer. Anyone who received advance premium tax credit payments through the Health Insurance Marketplace must also file to reconcile those credits.

When Filing Is Optional but Beneficial

Even when you’re not required to file, doing so is usually in your interest. If federal income tax was withheld from wages, a return is the only way to claim a refund. Refundable credits like the Earned Income Tax Credit and the Additional Child Tax Credit can only be claimed by filing. Filing also starts the statute of limitations for IRS examination and creates a documented record that can be important for mortgage applications, immigration proceedings, and financial planning.