What is IRMAA and how does it affect Medicare premiums?

IRMAA (Income-Related Monthly Adjustment Amount) is a surcharge added to Medicare Part B and Part D premiums for higher-income beneficiaries. Unlike tax brackets, IRMAA operates as a cliff: exceeding a threshold by even $1 triggers the full surcharge for that tier, which can add thousands of dollars annually to Medicare costs.

Why does IRMAA use income from two years ago?

IRMAA is calculated with a two-year lookback: your 2026 Medicare premiums are based on your 2024 tax return (MAGI). This delay means current-year income decisions affect premiums two years later, but it also provides planning time since you can anticipate future IRMAA exposure.

Does tax-exempt bond interest count toward IRMAA?

Yes. IRMAA uses Modified Adjusted Gross Income (MAGI), which includes tax-exempt municipal bond interest. This means municipal bond income, while exempt from federal income tax, still counts toward IRMAA thresholds and can trigger Medicare premium surcharges.

IRMAA Guide: Medicare Premium Surcharge Planning

Robert Stowe, AAMS® | Investment Advisor

If you've accumulated substantial retirement savings, Medicare has a "congratulatory" surcharge waiting for you. IRMAA, the Income-Related Monthly Adjustment Amount, can push Medicare Part B premiums from the standard $202.90 per month to over $689.90 per month per person. The surcharge exists because higher-income retirees are required to contribute more toward their Medicare costs. Understanding how IRMAA works, particularly its two-year lookback and cliff-based structure, helps explain why some retirees coordinate income timing with these thresholds.

This guide provides general educational information about IRMAA and Medicare premium surcharges. It is not personalized financial, tax, or healthcare advice. IRMAA thresholds and premium amounts are subject to annual adjustment. The strategies discussed may have tax consequences and may not be appropriate for all situations. Before making decisions about retirement income, Roth conversions, charitable giving, or Medicare enrollment, consult with qualified financial, tax, and healthcare professionals who can evaluate your specific circumstances.

What Is IRMAA?

IRMAA is a surcharge added to Medicare Part B (medical insurance) and Part D (prescription drug coverage) premiums for beneficiaries whose income exceeds certain thresholds. The program exists because Congress determined that higher-income retirees should contribute more toward Medicare costs, effectively creating a means-tested component to what is otherwise a universal program.

The surcharge applies specifically to Part B and Part D premiums. It does not affect Medicare Part A (hospital insurance) or Part C (Medicare Advantage) plans. This distinction matters because Part A is premium-free for most beneficiaries regardless of income, while Part C premiums are set by private insurers separately from IRMAA calculations.

The Financial Impact

For most Medicare beneficiaries, Part B costs a standard $202.90 per month in 2026. But for higher-income individuals, that premium can reach $689.90 per month, more than triple the base amount. For a married couple both subject to the highest IRMAA tier, the additional annual cost exceeds $11,700 compared to standard premiums.

This happens because IRMAA functions as a progressive surcharge: the higher your income, the larger the premium adjustment. Understanding where you fall on this scale, and how close you are to the next threshold, is essential for effective retirement income planning.

How IRMAA Is Calculated

The Social Security Administration determines IRMAA eligibility based on your Modified Adjusted Gross Income (MAGI). For IRMAA purposes, MAGI equals your Adjusted Gross Income (AGI) plus tax-exempt interest income. This definition creates an important consequence: municipal bond interest, while exempt from federal income tax, still counts toward the IRMAA calculation.

The calculation operates on a sliding scale with distinct income tiers. Once your MAGI exceeds the lowest threshold, the surcharge applies to your entire premium, not just the income above the threshold. This "cliff" structure fundamentally differs from how income tax brackets work and creates both risk and opportunity for strategic planning.

The Cliff Danger: Why $1 Matters

Unlike income tax brackets, where only income above each threshold faces the higher rate, IRMAA operates as a cliff system. Exceeding a threshold by even one dollar pushes you into the next tier, and you owe the higher premium for the entire year. This structure creates scenarios where a small amount of additional income triggers disproportionately large premium increases.

Income Tax Brackets

How they work: Only income above each threshold is taxed at the higher rate. Earning $1 more than a bracket threshold costs you only a fraction of a dollar in additional tax.

The math: If the 22% bracket starts at $100,000 and you earn $100,001, only that $1 is taxed at 22%, costing you $0.22 in additional tax.

Result: Marginal increases in income produce marginal increases in tax liability.

IRMAA Cliffs

How they work: Exceeding a threshold by any amount triggers the full surcharge for that tier. Earning $1 over the threshold costs you the entire premium increase for the year.

The math: If the threshold is $218,000 for a married couple and you earn $218,001, you're bumped to the next tier, adding approximately $975 per person annually in additional premiums.

Result: A single dollar of excess income can cost thousands in additional Medicare costs.

A Costly Example

Consider a married couple with joint MAGI of $218,000, exactly at the first threshold. They realize a $2,000 capital gain from selling a small investment position, pushing their MAGI to $220,000.

That $2,000 gain triggers the first IRMAA tier for both spouses. Each person's Part B premium increases from $202.90 to $284.10 monthly, plus the Part D surcharge of $14.50 each. The annual cost increase: approximately $1,949 for the couple.

Bottom line: A $2,000 capital gain cost them $1,949 in additional Medicare premiums, an effective 97% tax rate on that income when IRMAA is factored in. Understanding these cliff effects is essential for year-end tax planning.

The Two-Year Lag: Why 2024 Determines 2026

IRMAA operates with a two-year lookback: your Medicare premiums for any given year are determined by your tax return from two years prior. Your 2026 premiums are based on your 2024 income, and decisions you make about income in 2026 won't affect Medicare costs until 2028.

This delay creates both planning challenges and opportunities. The challenge is that income decisions made today have delayed consequences, consequences that arrive when your financial situation may have changed significantly. The opportunity is that the delay provides time to plan strategically, particularly in years leading up to Medicare enrollment.

The Planning Challenge

You might sell a property or realize substantial capital gains in 2026, feeling flush with cash. But the IRMAA impact doesn't arrive until 2028, potentially when cash flow is tighter or you've moved to a different financial phase.

This timing mismatch explains much of the poor IRMAA planning that occurs. Decisions feel disconnected from their consequences, making it easy to trigger unnecessary surcharges without realizing the full cost.

The Planning Opportunity

The two-year delay means you have visibility into upcoming IRMAA exposure. You know your 2024 income, so you can calculate your 2026 premiums precisely. Similarly, decisions made now affect 2028, giving you time to structure income strategically.

This visibility enables proactive planning: managing Roth conversions, timing asset sales, and structuring retirement income to stay below cliff thresholds when possible.

The Timeline to Track

Understanding which tax year affects which premium year is essential for planning:

2024 tax return → Determines 2026 Medicare premiums
2025 tax return → Determines 2027 Medicare premiums
2026 tax return → Determines 2028 Medicare premiums

2026 IRMAA Brackets (Based on 2024 Income)

The following table shows the official IRMAA thresholds and surcharges for 2026, which are determined by your 2024 Modified Adjusted Gross Income. Note that these surcharges apply per person. If you're a married couple both on Medicare, you must double the surcharge cost to calculate total household impact.

Individual MAGI	Joint Return MAGI	Part B Premium	Part D Surcharge	Total Monthly (Per Person)
≤ $109,000	≤ $218,000	$202.90 (Standard)	$0	$202.90 + Plan Premium
$109,001 – $137,000	$218,001 – $274,000	$284.10	$14.50	$298.60 + Plan Premium
$137,001 – $171,000	$274,001 – $342,000	$405.80	$37.50	$443.30 + Plan Premium
$171,001 – $205,000	$342,001 – $410,000	$527.50	$60.40	$587.90 + Plan Premium
$205,001 – $499,999	$410,001 – $749,999	$649.20	$83.30	$732.50 + Plan Premium
≥ $500,000	≥ $750,000	$689.90	$91.00	$780.90 + Plan Premium

MAGI Definition for IRMAA

For IRMAA calculations, Modified Adjusted Gross Income equals your Adjusted Gross Income (AGI) plus tax-exempt interest income. This means municipal bond interest, while free from federal income tax, counts toward IRMAA thresholds. This distinction catches many retirees by surprise, particularly those who hold substantial municipal bond positions for tax efficiency.

Georgia Residents: Senior Deduction Interaction

Georgia offers a generous retirement income exclusion of up to $65,000 per person (age 65+) from state taxes. However, this state-level exclusion has no impact on federal IRMAA calculations. Your full retirement income counts toward MAGI for IRMAA purposes regardless of how much Georgia exempts from state tax.

This creates an important distinction: strategies that reduce federal AGI (like QCDs or timing income recognition) affect both Georgia state taxes and IRMAA calculations. Strategies that only qualify for Georgia's retirement exclusion provide state tax relief but have no IRMAA impact.

Strategies Some Retirees Consider

Your 2024 tax return already determines your 2026 premiums. The following approaches are used by some retirees to manage MAGI in future years. Each involves trade-offs and may not be appropriate for all situations.

Qualified Charitable Distributions (QCDs)

The problem: Required Minimum Distributions from traditional IRAs force taxable income onto your return, pushing up MAGI regardless of whether you need the money for living expenses.

The solution: If you're over age 70½, you can send up to $108,000 directly from your IRA to qualified charities through a Qualified Charitable Distribution. This transfer satisfies your RMD requirement but doesn't appear on your tax return as income.

Why it works: The QCD is "invisible" to IRMAA calculations. The money leaves your IRA, satisfies tax law requirements, supports causes you care about, and keeps your MAGI lower. For charitably-inclined retirees, QCDs are among the most effective IRMAA defenses available.

The Municipal Bond Trap

The problem: Many high-net-worth retirees hold municipal bonds for their tax-free interest. But while that interest avoids income tax, it's added back when calculating MAGI for IRMAA purposes.

The trap revealed: A retiree might choose municipal bonds specifically for tax efficiency, only to discover that the "tax-free" income pushed them into a higher IRMAA tier, potentially costing more than the taxes avoided.

The solution: Calculate whether your tax-exempt interest is pushing you over an IRMAA cliff. In some cases, taxable corporate bonds actually cost less when IRMAA impact is factored in alongside income taxes.

Strategic Roth Conversions

The opportunity: Converting traditional IRA funds to Roth creates taxable income now to reduce future taxes. When done strategically, you can fill up the space within an IRMAA bracket without crossing into the next tier.

The strategy: If you're $10,000 below the next IRMAA cliff, you can convert up to $9,000 to Roth. You pay income tax on the conversion, move money into a tax-free account, but stay in the lower premium tier.

The consideration: Large Roth conversions can push income over IRMAA thresholds. A conversion that saves $5,000 in future taxes but triggers $8,000 in IRMAA surcharges may not be advantageous. Consult a tax professional to evaluate the trade-offs.

The "Fill the Bracket" Concept

Some retirees calculate how much room remains within their current IRMAA tier and consider whether Roth conversions, capital gains realization, or other income could fit within that space without crossing the next threshold.

This type of coordination involves complex trade-offs between current taxes, future taxes, and Medicare premiums. A tax professional can help evaluate whether this approach makes sense for a given situation.

Life-Changing Events: The Appeal Option

The two-year lookback creates hardship when your current income differs dramatically from the reference year. The Social Security Administration recognizes this problem and provides an appeal process for specific "life-changing events" that significantly reduce income.

If you experienced any of the following events in 2025 or 2026, you may qualify to have IRMAA calculated using current income rather than the two-year-old figure:

Retirement or Reduced Work

If you stopped working or significantly reduced work hours, resulting in lower income than reflected in the lookback period.

Death of Spouse

If your spouse passed away and household income dropped as a result, particularly if the deceased spouse had significant earnings.

Divorce or Annulment

If you divorced and filing status changed from joint to individual, potentially moving you to different threshold amounts.

Loss of Income-Producing Property

If you lost income-producing property due to disaster or circumstances beyond your control.

What Does NOT Qualify as a Life-Changing Event

A common misconception: voluntary financial decisions that increase income are not appealable events. This distinction is critical because many retirees assume they can appeal IRMAA surcharges caused by "one-time" income events. They cannot.

The following do NOT qualify for IRMAA reconsideration, regardless of whether they were one-time events:

Roth conversions that spiked income in the lookback year
One-time capital gains from selling appreciated property or investments
Exercising stock options or RSU vesting events
Taking a lump-sum pension distribution
Realizing gains from selling a business
Required Minimum Distributions (even if they pushed you over a threshold)
Inheritance or windfall income

The "one-time income" trap: The SSA does not distinguish between recurring and non-recurring income for appeal purposes. If you executed a large Roth conversion, sold a property, or realized significant capital gains two years ago, you will pay the higher IRMAA premium for the full year based on that income. The fact that it was "one-time" or "unusual" provides no basis for appeal. This makes planning the timing of large income events around IRMAA thresholds essential.

Filing the Appeal

To request reconsideration based on a life-changing event, you must file Form SSA-44 with the Social Security Administration. This form allows you to document the qualifying event and provide evidence of your current (lower) income.

This appeal represents one of the few situations where the government grants a "do-over" on IRMAA calculations. If your circumstances qualify, pursuing this appeal can save thousands of dollars in premium surcharges.

Year-End Considerations

Some retirees review their income position relative to IRMAA thresholds as the year draws to a close. The following factors may be relevant when discussing year-end planning with a tax professional:

Factors to Review

Current income position: Year-to-date income relative to IRMAA thresholds. The distance to the next cliff affects how additional income would impact Medicare premiums.

Capital gains and losses: Realized gains increase MAGI; realized losses can offset gains. The timing of these transactions affects which tax year they fall into.

Transaction timing: Large transactions like property sales affect the tax year in which they close. Transactions in December versus January have different IRMAA implications due to the two-year lookback.

QCDs for those 70½+: Qualified Charitable Distributions satisfy RMD requirements without adding to MAGI. This may be relevant for charitably inclined retirees.

Roth conversion calculations: Conversions add to current-year income. The amount of "room" within a given IRMAA tier affects how much can be converted without crossing a threshold.

Understanding the Gap

The distance between current income and the next IRMAA threshold indicates how much additional income would trigger the next tier's surcharge. Someone $50,000 below a threshold has different flexibility than someone $1,000 away.

A tax professional can help calculate this gap and evaluate how planned transactions might affect future Medicare premiums.

Key Takeaways

IRMAA operates as a cliff, not a gradual increase. Exceeding a threshold by even one dollar triggers the full surcharge for that tier. This structure creates scenarios where small amounts of additional income produce disproportionately large Medicare premium increases, making precise income management essential.

The two-year lookback requires forward planning. Your 2026 Medicare premiums are determined by your 2024 income, and decisions made in 2026 won't affect premiums until 2028. This delay means income decisions made today have consequences that arrive when your financial situation may look quite different.

Municipal bond income counts toward IRMAA. Tax-exempt interest from municipal bonds is added back when calculating MAGI for IRMAA purposes. This catches many retirees by surprise and can make "tax-free" income more expensive than anticipated when surcharges are factored in.

QCDs are among the most effective defensive tools. For retirees over 70½ who are charitably inclined, Qualified Charitable Distributions satisfy RMD requirements without appearing as income on your tax return, making that income invisible to IRMAA calculations.

Life-changing events allow appeals. If your income dropped dramatically due to retirement, death of a spouse, divorce, or loss of income-producing property, you can file Form SSA-44 to have IRMAA calculated on current income rather than the two-year-old figure.

Bottom Line: IRMAA is a significant cost for successful savers, but its cliff-based structure and two-year lookback create opportunities for strategic planning. Understanding exactly where you stand relative to thresholds, and having strategies in place to manage income around those cliffs, can save thousands of dollars annually in Medicare premium surcharges.

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