What is Adjusted Gross Income (AGI)?

Adjusted gross income (AGI) is your total income for the year minus a specific set of deductions the IRS calls adjustments to income. It appears on line 11 of Form 1040 and is the number most tax rules key off, which makes it arguably the single most consequential figure on your return.

AGI is not your taxable income. Taxable income comes later, after you subtract the standard or itemized deduction. AGI sits between the two, and its position matters: lowering AGI can qualify you for benefits that lowering taxable income cannot.

How AGI Is Calculated

AGI = Gross Income - Adjustments to Income

Gross income covers wages, self-employment income, interest, dividends, capital gains, rental income, retirement distributions, and the taxable portion of Social Security.

Adjustments, sometimes called above-the-line deductions, are subtracted whether or not you itemize. The common ones:

• Deductible traditional IRA contributions
• Health Savings Account (HSA) contributions made outside payroll
• Student loan interest, up to $2,500
• One half of self-employment tax
• SEP, SIMPLE, and solo 401(k) contributions for the self-employed
• Educator classroom expenses
• Alimony paid under divorce agreements finalized before 2019

A common misconception: 401(k) and 403(b) contributions are not adjustments. They never appear in your gross income to begin with, since your employer excludes them from Box 1 of your W-2. They reduce AGI, just through a different mechanism, which is why you will not find them listed on Schedule 1.

Why AGI Matters More Than Taxable Income

AGI, or a modified version of it, controls eligibility for a long list of tax benefits. Cross a threshold by a dollar and you can lose thousands.

The medical expense floor shows why the ordering matters: a lower AGI both increases the deduction and can qualify you for credits, while an itemized deduction reduces taxable income without touching any of these thresholds.

AGI vs. MAGI

Modified adjusted gross income (MAGI) is AGI with certain items added back. The catch is that MAGI is not one number. Each provision defines it slightly differently.

For Roth IRA eligibility, MAGI adds back the student loan interest deduction and a few exclusions. For ACA subsidies, it adds back tax-exempt interest, untaxed Social Security, and the foreign earned income exclusion. For IRMAA, it is AGI plus tax-exempt interest.

For most people with straightforward finances, MAGI and AGI are the same or nearly so. The difference matters most for people with municipal bond interest, foreign income, or significant untaxed Social Security.

Lowering Your AGI

The levers are limited, because adjustments are a fixed statutory list, but the ones that exist are meaningful:

Contributing to a traditional 401(k) or 403(b) keeps income out of Box 1 entirely. HSA contributions reduce AGI and are the only deduction that also produces tax-free growth and tax-free qualified withdrawals. For the self-employed, a SEP or solo 401(k) can shelter a large share of business income.

Timing matters at the margins. Deferring a bonus, harvesting capital losses to offset gains, or shifting a Roth conversion into a lower-income year all move AGI. Retirees in the window between leaving work and claiming Social Security often have the most control, since they choose which accounts to draw from and therefore how much taxable income to recognize. Comparing withdrawal sequences against ACA and IRMAA thresholds in ProjectionLab’s tax analytics shows where a small change in AGI produces a large change in what you keep.

Frequently Asked Questions

Where do I find my AGI? Line 11 of Form 1040. You will also need last year’s AGI to verify your identity when e-filing.

What is the difference between AGI and taxable income? AGI is gross income minus adjustments. Taxable income is AGI minus your standard or itemized deduction, and it is the figure your tax brackets apply to.

Do 401(k) contributions reduce AGI? Yes, but indirectly. Pre-tax contributions are excluded from the wages reported on your W-2, so they never enter gross income. They are not listed as an adjustment because they were never counted.

Is MAGI the same as AGI? Usually close, rarely identical. MAGI adds back specific items and is defined differently for each provision that uses it. Check the definition for the specific benefit you are evaluating.

How can I lower my AGI? Pre-tax retirement contributions, HSA contributions, self-employed retirement plans, and deductible traditional IRA contributions. Timing income and harvesting capital losses help at the margin.

Does AGI include Social Security benefits? Only the taxable portion, which is zero to 85% of benefits depending on your other income. The untaxed portion stays out of AGI but is added back for some MAGI calculations, including ACA subsidies.