Line 38 on Form 1040 was your adjusted gross income (AGI), and it only appeared on returns for tax years before 2018. When the IRS redesigned Form 1040 for the 2018 filing season, that number moved. On the current form, AGI is on Line 11, and taxable income — the figure the IRS actually uses to calculate what you owe — is on Line 15.1Internal Revenue Service. Adjusted Gross Income
If someone tells you to check “Line 38 for your taxable income,” they’re working from an outdated form and using the wrong term. Line 38 was never taxable income. It was AGI, one step earlier in the calculation.
What Line 38 Reported on the Old Form 1040
Before 2018, Form 1040 stretched across two full pages with more than 70 numbered lines. Line 38 sat at the bottom of page one and reported adjusted gross income: a subtotal reached after subtracting certain “adjustments to income” from your total earnings, but before applying any standard or itemized deduction.2Internal Revenue Service. 2017 Form 1040 U.S. Individual Income Tax Return
Taxable income — the number that actually determined your tax bill — came further down the return, on Line 43. So on the old form, the sequence was: total income, then Line 38 (AGI), then deductions, then Line 43 (taxable income), then the tax calculation.
Where Those Numbers Are on the Current Form 1040
The redesigned Form 1040 condensed everything. Two lines now do the work that used to be spread across dozens:
- Line 11 shows your adjusted gross income (the old Line 38).
- Line 15 shows your taxable income (the old Line 43).
If a lender, financial aid form, or state return asks for the number that used to be on Line 38, pull it from Line 11 of your current federal return.
How AGI Is Calculated
AGI is your total gross income minus a specific set of deductions the IRS calls adjustments to income. You list these on Part II of Schedule 1, and the result flows to Line 11 of Form 1040.3Internal Revenue Service. Definition of Adjusted Gross Income
Gross income covers wages, salaries, tips, interest, dividends, capital gains, rental income, business income, and most other money you receive during the year. Common adjustments that reduce it include:
- Deductible traditional IRA contributions
- Health savings account contributions tied to a high-deductible health plan
- Half of self-employment tax, calculated on Schedule SE4Internal Revenue Service. Schedule SE (Form 1040) – Self-Employment Tax
- Student loan interest paid on qualified education loans
- Educator expenses up to $300 per eligible teacher
- Alimony paid under divorce or separation agreements finalized before 2019
- Early withdrawal penalties charged by a bank for pulling money from a time deposit early
The full list appears on Schedule 1.5Internal Revenue Service. Schedule 1 (Form 1040) – Additional Income and Adjustments to Income
From AGI to Taxable Income
After AGI on Line 11, you subtract either the standard deduction or your itemized deductions from Schedule A, whichever is larger. If you have qualifying business income, a separate deduction of up to 20% of that income goes on Line 13. What’s left on Line 15 is taxable income.
For the 2026 tax year, the standard deduction amounts are $16,100 for single filers or married filing separately, $32,200 for married filing jointly, and $24,150 for head of household.6Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 Taxpayers 65 or older qualify for an additional standard deduction, and for tax years 2025 through 2028 there is also an enhanced senior deduction worth $6,000 per qualifying individual ($12,000 for a joint-filing couple where both spouses are 65 or older), phased out above modified AGI of $75,000 for individuals or $150,000 for joint filers.7Internal Revenue Service. Check Your Eligibility for the New Enhanced Deduction for Seniors
Roughly 90% of filers take the standard deduction rather than itemizing. If your qualifying expenses (mainly state and local taxes, mortgage interest, charitable contributions, and medical expenses above 7.5% of AGI) exceed your standard deduction, Schedule A saves more.8Internal Revenue Service. Instructions for Schedule A (Form 1040)
Why the Difference Between AGI and Taxable Income Matters
AGI and taxable income look similar on the page but do different jobs, and confusing them is the whole reason “Line 38” still causes trouble.
AGI (Line 11) is the gatekeeper. Dozens of tax benefits phase in or out based on it. Roth IRA contributions, for example, phase out for single filers with modified AGI between $153,000 and $168,000 in 2026, and between $242,000 and $252,000 for married couples filing jointly.9Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 Medical expenses are deductible only to the extent they exceed 7.5% of AGI.10Internal Revenue Service. Topic No. 502, Medical and Dental Expenses The Child Tax Credit and other credits shrink or disappear as AGI rises. Lenders, colleges, and state tax agencies often ask for AGI as well, because it’s a cleaner measure of income than gross wages.
Taxable income (Line 15) is what the IRS actually plugs into the tax brackets. Below $100,000, you look up the tax owed in the Tax Table in Publication 1040; above $100,000, you use the Tax Computation Worksheet.11Internal Revenue Service. Publication 1040 – Tax and Earned Income Credit Tables The seven marginal brackets for 2026 run from 10% to 37%.12Internal Revenue Service. Federal Income Tax Rates and Brackets
Quick Reference: Old Line to New Line
- Old Line 38 (AGI) → Line 11 on the current Form 1040
- Old Line 43 (taxable income) → Line 15 on the current Form 1040
If you’re pulling a figure from an old return to enter on a new form or application, match the label rather than the line number. AGI on a 2017 return is still AGI on a 2025 return, even though it has moved thirty lines up the page.