8501 / Who must file a federal income tax return?

Married individuals are required to file a tax return if the individual’s gross income, when combined with his or her spouse’s gross income, is more than the standard deduction that applies to a joint return and (1) the individual and his or her spouse, at the close of the tax year, shared the same household, (2) the individual’s spouse does not file a separate return and (3) neither the individual nor his or her spouse is a dependent of another taxpayer who has income (other than earned income) in excess of $500.

A return must be filed by every individual whose gross income equals or exceeds the following limits in 2025:¹

(1)   Married persons filing jointly – $30,000 (if one spouse is 65 or older – $31,600; if both spouses are 65 or older – $33,200).

(2)   Surviving spouse – $30,000 (if 65 or older – $31,600).

(3)   Head-of-household – $22,500 (if 65 or older – $24,100).

(4)   Single persons – $15,000 (if 65 or older – $17,000).

(5)   Married persons filing separately – $15,000 (if 65 or older – $16,600).

(6)   Dependents – an individual who may be claimed as a dependent of another must file a return for 2025 if he has unearned income in excess of (1) $1,350 or (2) the sum of $450 and the individual’s earned income.

Taxpayers claiming the additional deduction for blindness may need to attach additional documents to a tax return to verify entitlement to the additional standard deduction.

Certain parents whose children are required to file a return may be permitted to include the child’s income over $1,350 (2025) on their own return, thus avoiding the necessity of the child filing a return (see Q 8602). The 2017 tax reform legislation provided new rules with respect to the unearned income of minors, which were repealed for tax years beginning in 2020. Absent the repeal, that income would have been taxed at the rates applicable to trusts and estates, while the earned income of minors would have been taxed at the ordinary income tax rates applicable to single filers. For the 2018 and 2019 tax years, taxpayers had the option of electing either set of rules.

A taxpayer with self-employment income must file a return if net self-employment income is $400 or more.

An individual who was subject to wage withholding but did not have gross income in excess of the threshold amounts described above may desire to file a return in order to receive a refund of the withheld taxes. Similarly, an individual not required to file a return may desire to file a return in order to receive a refund resulting from a refundable credit (a tax credit or refund payable to the taxpayer even if he or she had paid no tax), such as the earned income credit.

When filing a claim for refund, taxpayers should consider the mailbox rule, which takes the date of mailing into consideration rather than the date the IRS receives the return. A district court recently confirmed that the “mailbox rule” applies to govern the date a return claiming a refund is filed with the IRS. Claims for refunds can generally be made within the immediate three years preceding the date the claim is filed plus extensions. The ruling, which noted that the IRS has previously agreed to follow the mailbox rule in these situations, means that if an otherwise late return is also a claim for a refund or credit, the date mailed is considered the date filed even if it is mailed after the original due date for the return.²