Is MAGI Calculated Before or After the Standard Deduction?

Modified adjusted gross income is calculated before the standard deduction, not after. On Form 1040, your MAGI is built from the adjusted gross income on line 11, and the standard deduction is subtracted further down the form to reach taxable income.1Internal Revenue Service. Adjusted Gross Income That sequence matters, because MAGI controls eligibility for dozens of credits, deductions, and surcharges, and the standard deduction cannot move it by a single dollar.

Where MAGI Sits on Your Return

A federal return follows a set order. You add up wages, interest, rental income, and other income to reach total income on line 9. You then subtract above-the-line adjustments from Schedule 1, such as HSA contributions or student loan interest, to arrive at AGI on line 11.1Internal Revenue Service. Adjusted Gross Income MAGI starts from that AGI and adds back certain items depending on which tax provision is at issue.2Internal Revenue Service. Modified Adjusted Gross Income

Only after AGI and MAGI are already fixed does the standard deduction enter the return. It comes off AGI to produce taxable income, the figure your tax rate is applied to.3Office of the Law Revision Counsel. 26 USC 63 – Taxable Income Defined For 2026, the standard deduction is $16,100 for single filers, $32,200 for joint filers, and $24,150 for heads of household.4Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 Those amounts lower the tax you owe. They do not lower your MAGI.

Why the Order Matters

Because MAGI is locked in before the standard deduction is applied, you cannot use that deduction to slip under any MAGI threshold. That includes the thresholds for the most common tax benefits and obligations tied to income.

Roth IRA Contributions

For 2026, the Roth IRA contribution limit is $7,500, or $8,600 if you are 50 or older.5Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 The amount you can actually contribute phases out over these MAGI ranges:

  • Single or head of household: $153,000 to $168,000
  • Married filing jointly: $242,000 to $252,000
  • Married filing separately: $0 to $10,000

Contributing more than your MAGI allows triggers a 6% excise tax on the excess for each year it stays in the account.6Office of the Law Revision Counsel. 26 USC 4973 – Tax on Excess Contributions to Certain Tax-Favored Accounts and Annuities

Traditional IRA Deductions

If you or your spouse is covered by a workplace retirement plan, the traditional IRA deduction phases out based on MAGI. For 2026:5Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500

  • Single filer covered by a workplace plan: $81,000 to $91,000
  • Joint filers, contributing spouse covered: $129,000 to $149,000
  • Not covered, spouse is: $242,000 to $252,000
  • Married filing separately, covered: $0 to $10,000

If neither spouse has a workplace plan, no MAGI phase-out applies.

Child Tax Credit, Premium Tax Credit, NIIT, and IRMAA

The Child Tax Credit begins to phase out at $200,000 of MAGI for most filers and $400,000 for joint filers, reducing by $50 for every $1,000 above the threshold.7Office of the Law Revision Counsel. 26 USC 24 – Child Tax Credit Marketplace health insurance subsidies through the Premium Tax Credit are also sized to household MAGI, with a higher figure producing a smaller subsidy.8HealthCare.gov. Modified Adjusted Gross Income (MAGI) – Glossary

The 3.8% Net Investment Income Tax applies to the lesser of your net investment income or the amount by which MAGI exceeds $200,000 (single), $250,000 (joint), or $125,000 (married filing separately).9Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax Those thresholds are not indexed for inflation.

Medicare Part B and Part D premiums also rise for higher-income beneficiaries through Income-Related Monthly Adjustment Amounts. The Social Security Administration uses the MAGI from a return filed roughly two years earlier, so a 2024 return generally drives 2026 premiums.10Social Security Administration. Premiums: Rules for Higher-Income Beneficiaries For 2026, Part B surcharges begin once MAGI exceeds $109,000 for individuals or $218,000 for joint filers, and rise through five brackets to a top surcharge of $487.00 per month at $500,000 individual or $750,000 joint.11CMS. 2026 Medicare Parts A and B Premiums and Deductibles

Every one of these tests looks at MAGI, not taxable income. The standard deduction sits on the wrong side of the calculation to help.

MAGI Is Not a Single Number

One thing worth pinning down: MAGI is not one fixed figure. The starting point is always AGI, but each tax provision requires its own set of add-backs.2Internal Revenue Service. Modified Adjusted Gross Income The MAGI for taxable Social Security benefits adds back tax-exempt interest and exclusions under sections 135, 137, 221, and 911.12Office of the Law Revision Counsel. 26 USC 86 – Social Security and Tier 1 Railroad Retirement Benefits The MAGI for the Net Investment Income Tax adds back only excluded foreign earned income.9Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax The MAGI for the Premium Tax Credit adds back foreign earned income, tax-exempt interest, and nontaxable Social Security benefits.13eCFR. 26 CFR 1.36B-1 – Premium Tax Credit Definitions

What all of them share: none of them subtract the standard deduction. If you need MAGI for more than one purpose, run each calculation separately.

Common Add-Backs to AGI

A handful of items appear again and again when moving from AGI to MAGI:

  • Tax-exempt interest reported on Form 1040, line 2a (typically municipal bond interest).2Internal Revenue Service. Modified Adjusted Gross Income
  • Foreign earned income excluded under Section 911.
  • The portion of Social Security benefits that is not otherwise included in gross income.
  • Employer-provided adoption assistance, for Roth IRA and Coverdell ESA purposes.
  • Student loan interest and traditional IRA deductions, added back for IRA contribution eligibility.

What Can Actually Lower Your MAGI

Since the standard deduction is out of reach, the real levers are above-the-line adjustments that reduce AGI before MAGI is even calculated. Those adjustments live on Schedule 1 and directly reduce the line 11 figure that every MAGI formula starts from.14Office of the Law Revision Counsel. 26 USC 62 – Adjusted Gross Income Defined

  • Traditional 401(k), 403(b), and 457(b) contributions reduce W-2 wages before they reach your return. The 2026 401(k) limit is $24,500.5Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
  • HSA contributions reduce AGI and are generally not added back for most MAGI calculations.
  • The deductible half of self-employment tax.
  • Self-employed health insurance premiums, if you are not eligible for employer-sponsored coverage.
  • Up to $2,500 of student loan interest, though this one gets added back when calculating MAGI for IRA eligibility.2Internal Revenue Service. Modified Adjusted Gross Income

Some above-the-line deductions get added back for specific MAGI purposes, which is why 401(k) and HSA contributions tend to be the most reliable ways to bring MAGI down across the board.

A Worked Example

Say a single filer has $80,000 of AGI on line 11 and no items that require add-backs. MAGI is $80,000. Subtracting the $16,100 standard deduction produces $63,900 of taxable income, which is what the federal rate schedule is applied to. Roth IRA eligibility, IRMAA brackets, NIIT thresholds, and the rest of the MAGI-based tests all still look at the $80,000 figure. The deduction changed the tax bill. It did not change anything MAGI controls.