Modified Adjusted Gross Income
Adjusted gross income recalculated by adding back certain deductions and excluded income items, used by the IRS to determine eligibility for specific tax benefits such as Roth IRA contributions, the Net Investment Income Tax, and ACA premium tax credits.
Modified Adjusted Gross Income (MAGI) is not a single fixed calculation — rather, 'MAGI' is a concept that the IRS defines differently for different purposes by adding back specific deductions or exclusions to regular AGI. Understanding which version of MAGI applies to a given provision is essential, as the modifications can vary significantly.
For Roth IRA contribution eligibility in 2025, MAGI is calculated by adding back traditional IRA deductions, student loan interest deductions, and certain other items to AGI. The ability to contribute directly to a Roth IRA phases out between $150,000 and $165,000 of MAGI for single filers, and between $236,000 and $246,000 for married filing jointly. Taxpayers with MAGI above the upper limit cannot make direct Roth IRA contributions (though the 'backdoor Roth' strategy — contributing to a nondeductible traditional IRA and converting — remains available).
For the Net Investment Income Tax (NIIT), MAGI adds back foreign earned income exclusions to regular AGI. The NIIT applies to the lesser of net investment income or the amount by which MAGI exceeds $200,000 for single filers or $250,000 for joint filers.
For traditional IRA deductibility when one spouse is covered by a workplace plan but the other is not, a separate MAGI calculation applies. For Medicare premium surcharges (IRMAA), MAGI equals AGI plus tax-exempt interest income. For ACA marketplace premium tax credits, MAGI adds back foreign earned income, tax-exempt Social Security benefits, and certain other items.
For investors, MAGI management is particularly important because several high-value provisions hinge on staying below critical thresholds. Common strategies include maximizing pre-tax 401(k) contributions (which reduce AGI and thus MAGI for most purposes), making HSA contributions, timing the recognition of capital gains and ordinary income, and using installment sales to spread large capital gains across multiple years. Even a dollar above a MAGI threshold can trigger thousands of dollars in additional taxes or cause the loss of valuable deductions and credits.