IRMAA: Medicare's High-Income Surcharge Explained

Most Medicare beneficiaries pay a standard Part B premium — $185 per month in 2025. But if your income exceeds certain thresholds, you pay significantly more. This extra charge is called the Income-Related Monthly Adjustment Amount, or IRMAA — a surcharge that can add hundreds of dollars per month to your Medicare costs.

Understanding IRMAA is critical for anyone approaching Medicare eligibility with above-average retirement income. This guide explains how IRMAA is calculated, what the 2025 brackets are, and — importantly — how to appeal the surcharge when your income has recently dropped.

What Is IRMAA?

IRMAA is a means-tested premium surcharge applied to Medicare Part B and Medicare Part D (prescription drug coverage) for beneficiaries whose income exceeds defined thresholds. The surcharge is calculated by the Social Security Administration (SSA) and added directly to your monthly Medicare premiums.

The surcharge was created by the Medicare Modernization Act of 2003 and expanded over subsequent years. The intent is to have higher-income beneficiaries pay a larger share of Medicare’s true cost.

Key facts:

• IRMAA applies to both Part B and Part D premiums
• It’s based on your modified adjusted gross income (MAGI) from two years prior
• The SSA uses IRS tax data to determine your income — you don’t need to report it separately
• IRMAA is re-evaluated annually — if your income drops, your surcharge drops in the following year

How IRMAA Is Calculated

The SSA uses your MAGI from two years ago to determine your current-year IRMAA. In 2025, this means they’re looking at your 2023 tax return.

Your MAGI for IRMAA purposes is your adjusted gross income (AGI) plus any tax-exempt interest income (such as interest from municipal bonds). It does not include Social Security benefits unless those benefits are already included in your AGI.

Most people don’t need to calculate this themselves — SSA sends a letter in late fall (called an IRMAA determination letter) informing you of your upcoming premium level for the next year.

2025 IRMAA Brackets: Part B

The standard Part B premium is $185/month in 2025. IRMAA surcharges are in addition to this amount:

Note: Brackets are adjusted annually. Verify current-year amounts at Medicare.gov.

2025 IRMAA Brackets: Part D

IRMAA also applies to Part D drug coverage. The surcharge is added on top of whatever premium your specific plan charges:

The “Two-Year Lookback” Problem

The most frustrating aspect of IRMAA is the two-year lookback. If you retired in 2024 and your income dropped dramatically from 2023 to 2024, you’ll still be charged 2025 IRMAA based on your 2023 (pre-retirement) income.

This creates a situation where people who have recently retired face unexpectedly high Medicare premiums precisely when their income has dropped. The good news: there’s a formal appeal process to correct this.

Life-Changing Events That Allow IRMAA Appeals

You can request an IRMAA determination using a more recent year’s income if you experienced a qualifying “life-changing event”:

1. Marriage
2. Divorce or annulment
3. Death of a spouse
4. Work reduction (your hours were reduced by your employer)
5. Work stoppage (retirement, layoff, leaving work to care for a family member)
6. Loss of income-producing property (due to disaster, fraud, or other circumstances beyond your control)
7. Loss of pension income (e.g., your former employer’s pension plan terminated)
8. Receipt of settlement from an employer (employer bankruptcy or settlement)

Notably, a simple market downturn that reduced your investment income is not a qualifying life-changing event. But stopping work — even by choice — is.

How to Appeal IRMAA

The appeal is straightforward. File Form SSA-44 (“Medicare Income-Related Monthly Adjustment Amount — Life-Changing Event”) with your local Social Security office.

Required information:

• The specific life-changing event and when it occurred
• Your estimated income for the more recent year (or the year that better reflects your current situation)
• Supporting documentation (W-2s, tax returns, termination letter, pension termination notice)

You can file in person, by mail, or by calling SSA at 1-800-772-1213. If approved, SSA recalculates your IRMAA using the newer, lower income figure — potentially dropping you into a lower bracket or eliminating the surcharge entirely.

Appeal deadlines: You have until December 31 of the year following the year when the IRMAA took effect to appeal. File as soon as possible after your income drops.

IRMAA and Roth Conversion Strategy

One important tax planning consideration: Roth IRA conversions increase your MAGI in the conversion year and can push you into a higher IRMAA bracket two years later.

For example, if you do a large Roth conversion in 2025 that pushes your 2025 MAGI above $106,000, you’ll face IRMAA surcharges in 2027.

This doesn’t mean Roth conversions are bad — the long-term tax benefits often outweigh IRMAA costs — but the surcharge is a real cost to factor into conversion calculations. A financial planner familiar with Medicare can help you model the full impact.

Similarly, large capital gains events, Required Minimum Distributions (RMDs) that push income above thresholds, or large IRA withdrawals can all trigger IRMAA. Understanding your MAGI in retirement is part of effective Medicare cost planning.

Married Filing Separately: A Costly Status

If you’re married and file your taxes separately, you face much harsher IRMAA treatment. The “married filing separately” brackets are nearly identical to single filer brackets above $106,000, but there’s no lower threshold — even modest income above $106,000 triggers the second-highest surcharge.

Most married couples who file separately do so for specific legal or financial reasons. If that’s your situation, be aware of the IRMAA impact. Filing jointly often significantly reduces your combined IRMAA burden.

Comparing IRMAA to Other Medicare Cost Considerations

IRMAA affects your premiums, but there are other Medicare cost variables worth comparing:

• Medigap vs. Medicare Advantage: If you’re paying high IRMAA surcharges on Part B, your total Medicare cost equation shifts significantly. See our comparison of Medicare Advantage vs. Original Medicare to understand how the two systems interact with IRMAA.

• Part D drug coverage: If your IRMAA surcharge on Part D makes your total drug coverage costs high, it’s worth shopping plans during open enrollment. See our guide to Medicare Part D for details.

• Lower-income beneficiaries: If your income is low rather than high, Medicare Savings Programs may help reduce your Part B premium rather than add to it.

Key Takeaways

• IRMAA is a surcharge on Medicare Part B and Part D premiums for higher-income beneficiaries
• In 2025, single filers with income above $106,000 and joint filers above $212,000 are subject to IRMAA
• The surcharge is based on income from two years prior (your 2023 return determines 2025 IRMAA)
• If your income dropped due to retirement, divorce, death of spouse, or other qualifying events, you can appeal using Form SSA-44
• Roth conversions, large capital gains, and RMDs can all push you into IRMAA brackets — factor this into retirement tax planning
• IRMAA is re-evaluated each year; a drop in income this year will reduce your surcharge two years from now