What Income Counts Toward IRMAA MAGI in 2026?

What Is IRMAA MAGI?

For IRMAA, the Social Security Administration defines MAGI using a deliberately short formula. Start with the adjusted gross income on Form 1040, line 11, then add the tax-exempt interest reported on line 2a. SSA’s current Program Operations Manual describes that definition directly.

The IRMAA MAGI Formula

IRMAA MAGI = Form 1040 AGI (line 11) + tax-exempt interest (line 2a)

This is the Medicare IRMAA definition. Do not substitute a different MAGI formula used for an IRA contribution, ACA premium tax credit or another tax rule.

The formula is easy. Building the AGI underneath it is where the real work happens. Wages, taxable retirement distributions, recognized investment income and other items flow through the tax return before line 11. Then Medicare’s definition adds tax-exempt interest back on top.

Definition

AGI is not the same as taxable income. AGI appears before the standard or itemized deduction. Taxable income comes later on Form 1040. That ordering is why a deduction can lower your taxable income without lowering the MAGI Medicare uses for IRMAA.

What Income Counts Toward IRMAA?

A better rule than “cash received counts” is this: ask what amount reaches AGI, then check whether IRMAA has a special add-back. That one test prevents a surprising number of mistakes.

This is also why broad statements like “all IRA withdrawals count” are too crude. IRS Publication 590-B explains that a traditional IRA distribution can be partly nontaxable when the IRA contains nondeductible contributions. The taxable portion is the part that feeds AGI.

For a faster first-pass check of a specific income source, the IRMAA Income Checker can help you identify the likely tax-return path before you build the final MAGI number.

• Qualified Roth IRA distributions: generally excluded from gross income.
• Return of Roth IRA regular contributions: generally not included in gross income, although nonqualified Roth distributions can contain taxable earnings depending on the ordering rules and facts.
• Qualified HSA distributions: distributions used for qualified medical expenses are generally tax-free, so they do not increase AGI.
• Gifts and inheritances received: the receipt itself is generally not federal income to the recipient. Later income produced by the property—or a taxable gain when it is sold—can be a different story.
• Life-insurance death benefits: generally excluded from gross income when paid because of the insured person’s death, subject to exceptions.
• Loan proceeds, including reverse-mortgage borrowing: borrowed money generally is not income because it creates an obligation to repay.

That is why “use Roth money to avoid IRMAA” is not a universal strategy. A withdrawal from an existing qualified Roth can be MAGI-friendly; creating more Roth money through a conversion can increase MAGI first. The timing tradeoff belongs in the dedicated Roth conversion and IRMAA tradeoff guide.

This is why charitable giving can create confusion. A normal charitable deduction may help taxable income if you itemize, but it does not automatically lower AGI. A qualifying QCD works differently: the eligible amount sent directly from the IRA to charity is generally excluded from income in the first place. That distinction is covered in depth in QCD vs. standard charitable deduction for IRMAA.

That sounds like a small tax-form distinction. In practice it is one of the biggest sources of bad IRMAA estimates. Someone can have taxable income below a familiar tax-bracket number and still have IRMAA MAGI above a Medicare threshold because the two calculations start from different places.

For a real return, do not rebuild AGI from memory if you already have the filed tax return. Use the return and supporting schedules. Then investigate any unusual item—IRA basis, Roth distribution, property sale, rental loss, business loss, annuity exclusion ratio—where “cash received” and “taxable amount” are not the same thing.

That processing job belongs to the official 2026 IRMAA bracket-values guide if you only need the current numbers. If you want the full tax-year-to-premium sequence, use the Medicare calculation guide linked near the top of this article.

Bottom Line

IRMAA MAGI is usually straightforward once AGI is right: line 11 AGI plus line 2a tax-exempt interest. The part worth slowing down for is the transaction underneath AGI. Use the taxable portion, recognized gain or net business/rental result that actually reaches the return—not the gross amount of cash that moved.