Your taxable income on Form 1040 sits on Line 15, on page 2 of the return. That is the figure the IRS runs through the tax brackets to determine what you owe, and it is almost always lower than the adjusted gross income shown one page up on Line 11. The gap between the two is your deductions.1Internal Revenue Service. About Form 1040, U.S. Individual Income Tax Return
Where to Look on the Form
Flip to page 2 of Form 1040 and read down the right-hand column to Line 15. If you earned less than the standard deduction for your filing status and have no other taxable items, Line 15 may show zero, which means you have no federal income tax liability for the year.
The lines just above Line 15 show how the number was built. Line 11 is your AGI. Line 12 is your standard or itemized deduction. Line 13 is any qualified business income deduction, which applies to eligible self-employed filers and small business owners. Line 14 adds Lines 12 and 13 together. Line 15 is Line 11 minus Line 14.
If you file with tax software, the same lines appear on the return the program generates. Look for the “tax summary,” “review,” or “tax return PDF” screen before you submit and confirm Line 15 there.
How the Number Is Built
Three stages get you from what you earned to what the IRS taxes.
Total Income on Lines 1 Through 9
Page 1 of the 1040 collects every category of income the IRS treats as taxable: W-2 wages, 1099 freelance earnings, interest, dividends, retirement distributions, Social Security benefits, capital gains, rental income, and the rest. Most income counts unless a specific law excludes it, and income received as property or services counts too.2Internal Revenue Service. Taxable Income The total lands on Line 9.
Adjustments on Line 10, Then AGI on Line 11
Certain deductions come off before AGI is calculated. These are reported on Schedule 1 and include contributions to a health savings account (up to $4,400 for self-only coverage or $8,750 for family coverage in 2026), the deductible portion of self-employment tax, traditional IRA contributions, and student loan interest up to $2,500.3Internal Revenue Service. Expanded Availability of Health Savings Accounts Under the One, Big, Beautiful Bill Act Tax preparers often call these “above-the-line” deductions because they sit above the AGI line. The Schedule 1 total flows to Line 10, and Line 11 is Line 9 minus Line 10. That is your AGI.
Deductions on Lines 12 and 13, and Taxable Income on Line 15
From AGI, you subtract either the standard deduction or your total itemized deductions from Schedule A, whichever is larger, on Line 12. Line 13 subtracts any qualified business income deduction. Line 14 totals the two. Line 15 is what remains, and that is your taxable income.
AGI and Taxable Income Are Not the Same Thing
People often use “income” as if it meant one thing on a tax return. It doesn’t. AGI on Line 11 is the number outside institutions actually ask for. Mortgage lenders, the FAFSA, and Medicaid eligibility rules all reference AGI or a modified version of it, not taxable income. When a form asks for your “income” and points to your tax return, it almost always means Line 11.1Internal Revenue Service. About Form 1040, U.S. Individual Income Tax Return
Taxable income on Line 15 is always lower than AGI for anyone who takes a deduction, which is nearly everyone. The gap equals whatever is on Line 14. Two people with the same salary can have the same AGI and still owe very different amounts of tax, because one might have $15,000 in itemized deductions from mortgage interest and charitable gifts while the other takes the standard deduction. Their Line 15 figures diverge, and so do their tax bills.
2026 Standard Deduction Amounts
Most filers take the standard deduction rather than itemizing, so this is usually the number that controls the gap between Line 11 and Line 15. For tax year 2026:4Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
- Single: $16,100
- Married filing jointly: $32,200
- Head of household: $24,150
- Married filing separately: $16,100
Filers who are 65 or older or blind receive an additional standard deduction on top of these amounts. For 2026, that addition is roughly $2,000 for single filers and heads of household, or about $1,600 per qualifying spouse on a joint return. The One, Big, Beautiful Bill Act also created an enhanced senior deduction for tax years 2025 through 2028 worth an extra $6,000 per person, or $12,000 for a married couple filing jointly when both spouses qualify.5Internal Revenue Service. 2026 Filing Season Updates and Resources for Seniors A single filer age 65 or older can therefore reach a total standard deduction above $24,000 in 2026, and taxable income on Line 15 stays at zero until AGI clears that combined amount.
Itemizing on Schedule A only makes sense when your deductible expenses beat the standard deduction. The common categories are mortgage interest reported on Form 1098, state and local taxes up to $10,000, charitable contributions, and medical expenses that exceed 7.5% of your AGI.6Internal Revenue Service. Publication 502 (2025), Medical and Dental Expenses7Internal Revenue Service. About Form 1098, Mortgage Interest Statement
How Line 15 Turns Into a Tax Bill
Federal income tax is progressive: only the dollars within each range are taxed at that range’s rate. The 2026 brackets for single filers and married couples filing jointly are:4Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
Single filers:
- 10% on taxable income up to $12,400
- 12% on $12,401 to $50,400
- 22% on $50,401 to $105,700
- 24% on $105,701 to $201,775
- 32% on $201,776 to $256,225
- 35% on $256,226 to $640,600
- 37% on income over $640,600
Married filing jointly:
- 10% on taxable income up to $24,800
- 12% on $24,801 to $100,800
- 22% on $100,801 to $211,400
- 24% on $211,401 to $403,550
- 32% on $403,551 to $512,450
- 35% on $512,451 to $768,700
- 37% on income over $768,700
Landing in the 24% bracket does not mean everything you earn is taxed at 24%. Only the dollars above the 22% ceiling are. That is why your effective rate is always lower than your marginal bracket.
A Worked Example
Say you’re single, you earned $65,000 in wages with no other income, and you contributed $3,000 to a traditional IRA. You have no reason to itemize. The 1040 flows this way:
- Total income (Line 9): $65,000
- IRA deduction from Schedule 1 (Line 10): $3,000
- AGI (Line 11): $62,000
- Standard deduction (Line 12): $16,100
- Taxable income (Line 15): $45,900
That $45,900 sits inside the 12% bracket for single filers. The first $12,400 is taxed at 10% ($1,240), and the remaining $33,500 is taxed at 12% ($4,020), for a federal tax of about $5,260. The effective rate on the full $65,000 salary works out to roughly 8.1%, even though the marginal bracket is 12%.
Finding Taxable Income From a Prior Year
If you need Line 15 from a past return for a loan application, financial aid form, or your own records, the fastest source is the IRS Individual Online Account, which lets you view, print, or download transcripts and see your prior-year AGI after identity verification.8Internal Revenue Service. Get Your Tax Records and Transcripts
If the online tool isn’t an option, call the IRS automated transcript line at 800-908-9946 to have a transcript mailed to the address on file. Mailed transcripts typically arrive within 5 to 10 calendar days. For a full photocopy of a return rather than a summary transcript, submit Form 4506, which takes longer and carries a fee.
If you filed with tax software, logging back in usually lets you open saved returns from prior years. Line 15 is always where the taxable income sits, regardless of the tax year, since the current layout of the 1040 has used that line placement since 2018.