What this line means
Your adjusted gross income minus your deductions (standard or itemized) and qualified business income deduction, if any. This is the amount your federal income tax is calculated on. If the result is zero or negative, enter zero — you cannot have negative taxable income on this line.
Does this apply to you?
- You filed a return with any income after deductions
- You are determining your federal income tax bracket
- You are comparing the effect of standard vs. itemized deductions on your tax
- You have qualified business income from a sole proprietorship, partnership, or S corporation
- You want to confirm that the senior standard deduction reduced your taxable income correctly
Easy to overlook
The higher senior standard deduction can zero out taxable income A single filer 65 or older with $17,000 in total income and the 2025 senior standard deduction of $17,0001 has zero taxable income. Many seniors with modest Social Security and pension income owe no federal income tax once the additional standard deduction is applied, but they must still file if gross income exceeds the filing threshold. 2 IRS Form 1040-SR Instructions — Line 15
Qualified business income deduction reduces taxable income further If you have income from a sole proprietorship, partnership, or S corporation, the Section 199A qualified business income deduction (up to 20% of qualified business income) reduces taxable income on line 13. This deduction applies after the standard deduction, lowering line 15 further. Seniors with rental income through a pass-through entity often overlook this. 3 General filing pattern — negative taxable income errors
Watch out for this
Entering a negative number on line 15. If your deductions exceed your income, taxable income is zero — not a negative number. Negative taxable income does not generate a refund by itself. Capital loss carryforwards and net operating losses have separate rules for carrying excess amounts to future years.
Footnotes
-
IRS Revenue Procedure 2024-40, Section 3.01, Standard Deduction amounts for 2025. https://www.irs.gov/pub/irs-drop/rp-24-40.pdf ↩
-
IRS Form 1040-SR Instructions, Line 15. https://www.irs.gov/instructions/i1040sr ↩
-
IRS Form 8995 Instructions, Qualified Business Income Deduction. https://www.irs.gov/instructions/i8995 ↩