What Is Adjusted Gross Income? Definition, Calculation, and Uses

Adjusted gross income, or AGI, is your total income for the year minus a specific set of deductions the tax code lets you take before anything else is calculated. It appears on line 11 of Form 1040, and the IRS uses it more than any other single number to decide what credits you qualify for, how much you can deduct, what you pay for Medicare, and where you fall on income-based phaseouts. Every dollar you can legally subtract on the way to AGI saves you money on everything that follows.

What Counts as Income

Federal law casts a wide net. Gross income includes almost everything you earn or receive during the year unless a specific rule excludes it.¹

The common sources are wages, salaries, and tips from your W-2.² But the list runs longer than a paycheck. Interest from bank accounts and bonds reported on Form 1099-INT.³ Dividends on Form 1099-DIV. Capital gains from selling stocks or real estate. Net profit from self-employment or freelance work. Retirement distributions from pensions, 401(k)s, and IRAs, reported on Form 1099-R.⁴ Rental income, royalties, unemployment compensation, gambling winnings, and even jury duty pay all get added in.

Social Security benefits are a special case. Whether any portion counts depends on your “combined income” (half your benefit plus your other income, including tax-exempt interest). Single filers with combined income between $25,000 and $34,000 may owe tax on up to 50 percent of their benefits; above $34,000, up to 85 percent becomes taxable. The joint-filer thresholds are $32,000 and $44,000.

What Doesn’t Count

A handful of categories are excluded from gross income by statute. Treating any of them as income inflates your AGI and can cost you credits later.

Gifts and inheritances. Money or property received as a gift is not income to you. In 2026, a person can give up to $19,000 per recipient before the gift even has to be reported.⁵
Life insurance death benefits paid to a beneficiary.
Employer-paid health insurance premiums, which do not appear as income on your W-2.
Qualifying scholarships used for tuition and required fees (amounts covering room and board remain taxable).
Foreign earned income up to $132,900 in 2026, if you meet the physical presence or bona fide residence test.⁵

The Deductions You Subtract to Get to AGI

Once you have your gross income total, the law lets you subtract certain costs before calculating AGI. These are called above-the-line deductions because they sit above the AGI line on Form 1040.⁶ You get them whether you take the standard deduction or itemize.

Educator Expenses

K-12 teachers, counselors, principals, and aides who work at least 900 hours during the school year can deduct up to $350 in 2026 for unreimbursed classroom supplies, books, and professional development.⁷ Two eligible-educator spouses filing jointly can each claim up to $350.

Self-Employment Tax

Self-employed workers pay both halves of Social Security and Medicare taxes. To match traditional employees, whose employers cover half, you can deduct the employer-equivalent portion of that self-employment tax.

Traditional IRA Contributions

Contributions to a traditional IRA are deductible up to $7,500 for 2026, though the deduction phases out if you or your spouse are covered by a workplace retirement plan and your income crosses certain thresholds:⁸

Single with a workplace plan: phases out between $81,000 and $91,000.
Married filing jointly, contributor has a plan: $129,000 to $149,000.
Not covered, but spouse is covered: $242,000 to $252,000.

If neither spouse has a workplace plan, the full deduction is available at any income.

HSA Contributions

If you have a qualifying high-deductible health plan, HSA contributions made with after-tax dollars reduce gross income. The 2026 limit is $4,400 for self-only coverage and $8,750 for family coverage.⁹

Student Loan Interest

You can deduct up to $2,500 of student loan interest per year.¹⁰ In 2026 the deduction begins phasing out at $85,000 for single filers and $175,000 for joint filers, disappearing entirely at $100,000 and $205,000.

Other Adjustments

A few less common adjustments round out the list. Members of the Armed Forces relocating under military orders can deduct moving expenses. Performing artists and fee-based state or local officials can deduct certain work-related costs. Alimony paid under divorce agreements finalized before 2019 remains deductible. Each adjustment requires records, such as Form 1098-E for student loan interest.¹¹

How to Calculate Your AGI

The math is simple. Add up all your income, subtract your above-the-line deductions, and the result is your AGI. On Form 1040, the process works like this:¹²

Add all taxable income sources and enter the total on line 9 of Form 1040.
List above-the-line deductions on Schedule 1, Part II. The total from line 26 of Schedule 1 transfers to line 10 of Form 1040.
Subtract line 10 from line 9. The result on line 11 is your AGI.

A concrete example from the IRS: a taxpayer earns $50,000 in wages, $12,000 in rental income, $8,500 from a part-time job, and $500 in bond interest, totaling $71,000. They qualify for $250 in educator expenses and $2,500 in student loan interest, for $2,750 in adjustments. Their AGI is $71,000 minus $2,750, or $68,250.¹²

AGI Is Not Taxable Income

This trips people up constantly. AGI is not the number your tax bracket applies to. After you calculate AGI, you still subtract either the standard deduction ($16,100 for single filers, $32,200 for married filing jointly, or $24,150 for head of household in 2026) or your itemized deductions to arrive at taxable income.⁵ Taxable income is what determines the tax you actually owe.

AGI vs. Modified Adjusted Gross Income

Eligibility rules for many credits and retirement accounts refer to modified adjusted gross income, or MAGI. MAGI starts with your AGI and adds back certain deductions, and the frustrating part is that the add-backs change depending on which tax benefit is being calculated.¹³

For Roth IRA eligibility, MAGI equals AGI plus any traditional IRA deduction and student loan interest deduction you claimed. For the Premium Tax Credit used on marketplace health insurance, MAGI equals AGI plus foreign earned income, tax-exempt interest, and nontaxable Social Security benefits.¹³ For most people without foreign income, tax-exempt bonds, or nontaxable Social Security, MAGI and AGI are the same number.

A few 2026 MAGI thresholds worth knowing:

Roth IRA contributions phase out between $153,000 and $168,000 for single filers, and between $242,000 and $252,000 for married couples filing jointly.⁸
The $2,200-per-child Child Tax Credit begins phasing out at $200,000 for single filers and $400,000 for joint filers.¹⁴
The student loan interest deduction phases out between $85,000 and $100,000 for single filers, and between $175,000 and $205,000 for joint filers.

Why Your AGI Matters

AGI is the gatekeeper for dozens of tax benefits and financial rules. A few thousand dollars in either direction can make real money appear or disappear.

Credits and Deductions

The Earned Income Tax Credit uses AGI to determine eligibility. The medical expense deduction only covers costs exceeding 7.5 percent of AGI, so a higher AGI raises the threshold before anything becomes deductible.¹⁵ At $80,000 in AGI, your medical bills need to exceed $6,000 before you can deduct a dollar.

Net Investment Income Tax

A 3.8 percent surtax applies to investment income (interest, dividends, capital gains, rental income) when MAGI exceeds $200,000 for single filers, $250,000 for joint filers, or $125,000 for married filing separately.¹⁶ The tax hits the lesser of your net investment income or the amount by which MAGI exceeds the threshold. Someone with $230,000 in MAGI and $50,000 in investment income owes the tax on $30,000, or $1,140.

Medicare Premiums

Higher earners pay more for Medicare. The Income-Related Monthly Adjustment Amount increases Part B and Part D premiums based on MAGI from two years earlier. For 2026, single filers with MAGI above $109,000 and joint filers above $218,000 pay surcharges that can add hundreds of dollars per month.¹⁷ At the top tier, individuals with MAGI of $500,000 or more pay $689.90 per month for Part B, against the standard $202.90. Because the surcharge uses income from two years earlier, a high-income 2024 hits your 2026 premiums.

State Taxes and Loan Applications

Most states with an income tax use federal AGI as the starting point for state calculations, so an inflated federal AGI cascades into a higher state bill. Lenders also look at the AGI line when evaluating mortgage and loan applications.

How to Find Last Year’s AGI

If you e-file, the IRS asks for last year’s AGI to verify your identity, and forgetting it is one of the most common reasons e-filed returns get rejected. Three ways to find it:¹²

IRS Online Account. Log in at irs.gov, open the Records and Status tab, and select the tax year.
Tax return transcript. Request a free transcript from the IRS; it shows most line items from your filed return, including AGI.
Last year’s Form 1040, line 11. If you used tax software, last year’s return is usually available in the same program.

If you didn’t file a return last year, enter $0 as your prior-year AGI when e-filing.

1
Office of the Law Revision Counsel. 26 USC 61 – Gross Income Defined
2
Internal Revenue Service. General Instructions for Forms W-2 and W-3 (2026)
3
Internal Revenue Service. About Form 1099-INT, Interest Income
4
Internal Revenue Service. About Form 1099-R, Distributions From Pensions, Annuities, Retirement or Profit-Sharing Plans, IRAs, Insurance Contracts, Etc.
5
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill
6
Office of the Law Revision Counsel. 26 USC 62 – Adjusted Gross Income Defined
7
Internal Revenue Service. Topic No. 458, Educator Expense Deduction
8
Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
9
Internal Revenue Service. Revenue Procedure 2025-19
10
Internal Revenue Service. Topic No. 456, Student Loan Interest Deduction
11
Internal Revenue Service. Publication 970 (2025), Tax Benefits for Education
12
Internal Revenue Service. Adjusted Gross Income
13
Internal Revenue Service. Modified Adjusted Gross Income
14
Internal Revenue Service. Child Tax Credit
15
Office of the Law Revision Counsel. 26 USC 213 – Medical, Dental, Etc., Expenses
16
Internal Revenue Service. Topic No. 559, Net Investment Income Tax
17
Centers for Medicare & Medicaid Services. 2026 Medicare Parts A and B Premiums and Deductibles