Medicare costs in retirement are often treated as a fixed line item in a financial plan. However, Medicare premiums are not necessarily fixed. For some beneficiaries, premiums are recalculated each year based on income reported from two years prior. As a result, a single high-income year may lead to higher Medicare premiums in subsequent years.
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What IRMAA Is
IRMAA (the Income-Related Monthly Adjustment Amount) is a premium surcharge applied to Medicare Part B (medical coverage) and Medicare Part D (prescription drug coverage) for beneficiaries above certain income thresholds. It is assessed separately for each part and added to whatever the standard premium is in a given year.
The surcharge is not a penalty. It is a means-tested adjustment built into the Medicare program. Higher-income beneficiaries pay a larger share of actual Medicare program costs; lower-income beneficiaries pay the standard premium, which is the same for everyone below the threshold.
IRMAA is determined by the Social Security Administration, which reviews federal tax data annually and issues premium notices to affected beneficiaries before the start of each year. The notices typically arrive in the fall and reflect the surcharge tier for the coming calendar year.
The Two-Year Lookback
The two-year lag is the defining feature of IRMAA from a planning perspective.
The SSA sets Medicare premiums for a given year using the most recently available federal tax return. Because tax returns for year N are typically filed by April of year N+1, and the SSA must set premiums before that return is available, the data in hand by late fall is the return from year N-2. The result:
Income from two years prior determines the IRMAA tier for the current year.
In concrete terms: income reportable on a 2024 federal tax return determines 2026 Medicare premiums. Income from 2025 will determine 2027 premiums.
This lag has a compounding implication. A retiree who experiences a single high-income year (from a large Roth conversion, the sale of a business or property, an unusually large required minimum distribution, or an employer settlement payment) will see that event reflected in Medicare premiums for the year two years later. Even if income returns to a lower level the very next year, the elevated premium persists for one full calendar year before the lower return year catches up in the lookback window.
| Income Year | IRMAA Year Affected |
|---|---|
| 2023 | 2025 |
| 2024 | 2026 |
| 2025 | 2027 |
This table illustrates the standard two-year lookback timing. In most years, the SSA uses the most recently filed return, which is typically two years prior. Verify current SSA procedures with Medicare or a qualified professional.
The IRMAA Brackets and Cost Tiers
IRMAA is not a smooth surcharge that scales proportionally with income. It operates in discrete tiers. A beneficiary who falls one dollar above a threshold pays the full surcharge for that tier, not just on the income above the line. This cliff structure means that the marginal cost of a single dollar of income at a threshold can be thousands of dollars in additional annual Medicare premiums.
The table below illustrates the approximate combined annual IRMAA cost for a married couple where both spouses are enrolled in Medicare, based on 2025 surcharge schedules. Single filer thresholds are roughly half the MFJ amounts shown.
| IRMAA Tier | MFJ MAGI Range | Single MAGI Range | Approx. Annual Surcharge (couple, Part B + D) |
|---|---|---|---|
| No surcharge | $212,000 or below | $106,000 or below | — |
| Tier 1 | $212,001–$266,000 | $106,001–$133,000 | ~$2,100 |
| Tier 2 | $266,001–$334,000 | $133,001–$167,000 | ~$5,300 |
| Tier 3 | $334,001–$400,000 | $167,001–$200,000 | ~$8,500 |
| Tier 4 | $400,001–$749,999 | $200,001–$499,999 | ~$11,700 |
| Tier 5 | $750,000 or above | $500,000 or above | ~$12,700 |
Based on 2025 IRMAA surcharge schedules (reflecting 2023 MAGI), which are adjusted annually by CMS. Annual figures assume both spouses are enrolled in Medicare Part B and Part D and are illustrative only. Verify current thresholds and surcharges with the SSA or a qualified professional.
A couple with combined income just above the first tier threshold would pay roughly $2,100 more per year than a couple just below it. A Roth conversion that pushes MAGI across a higher tier line would add several thousand dollars more annually, two years later, on top of the income tax paid in the conversion year. Because surcharge amounts and thresholds are adjusted each year, the planning value is understanding the structure and order of magnitude — not memorizing any specific figure.
How Common Income Events Trigger IRMAA
The two-year lookback interacts with several income events that are common in the years around retirement.
Roth Conversions. Converting traditional IRA assets to a Roth IRA increases MAGI in the year of conversion. For pre-retirees and early retirees executing partial conversions to reduce future RMD exposure, each conversion year needs to be evaluated not only for its immediate income tax cost but also for its effect on IRMAA two years out. A conversion that crosses a tier threshold by a small margin is not tax-efficient: the IRMAA surcharge in years two and three is part of the total cost of that conversion.
Required Minimum Distributions. RMDs from traditional IRAs and 401(k)s are mandatory under federal law beginning at age 73 (with SECURE 2.0 provisions that may raise this age to 75 for those born in 1960 or later, scheduled to take effect in 2033). RMD amounts are calculated based on account balances at the end of the prior year and IRS life expectancy tables. For retirees with substantial tax-deferred balances, RMDs alone may push MAGI above IRMAA thresholds, and those RMDs are not discretionary. In years with large RMDs, the IRMAA cost two years later is a predictable consequence of the account balance today.
Asset Sales. Selling a business, investment property, concentrated stock position, or a second home generates capital gain income that is included in MAGI. Installment sales that spread proceeds over multiple years may offer some control over when the income appears, but lump-sum dispositions can produce one-time income spikes large enough to move MAGI by hundreds of thousands of dollars in a single year, with direct IRMAA consequences two years later.
Employer Settlement Payments. Lump-sum payments from employer deferred compensation plans, litigation settlements, or executive severance arrangements may produce large one-time MAGI increases in the year of receipt.
The Cliff: One Dollar Matters
The step structure of IRMAA brackets is qualitatively different from how ordinary income tax brackets work. In the income tax system, a dollar of income above a bracket threshold is taxed at the higher rate: only that dollar, not the dollars below it. IRMAA is not marginal in that sense. The surcharge applies to the entire premium, not to the last dollar of income.
The practical consequence: in the year an income event brings MAGI near an IRMAA threshold, the difference between landing $1 below versus $1 above the line is thousands of dollars per year in additional Medicare premiums over the following two to three years (while the high-income year is in the lookback window and then exits it).
This makes income precision near IRMAA thresholds more consequential than precision near income tax bracket thresholds, where the incremental rate applies only to the marginal dollar.
Income control strategies (sizing a Roth conversion to stay below a threshold, timing year-end distributions, or deferring income to the following year) are therefore more valuable near IRMAA lines than they might appear from a tax-bracket perspective alone.
The SSA-44 Appeal: When Current Income Is Lower
The two-year lag creates genuine hardship when income decreases significantly after the lookback year. A retiree who earned substantial income in 2023 and then retired in 2024 would still face 2025 IRMAA surcharges based on the higher 2023 income, even if their current retirement income is well below the threshold.
The SSA provides a mechanism for relief: Form SSA-44, Medicare IRMAA Life-Changing Event. This form allows a beneficiary to request that SSA use a more recent year's income, or an estimate of the current year's expected income, to recalculate the IRMAA tier.
Qualifying Life-Changing Events
To use Form SSA-44, the reduction in income must be tied to one of the following qualifying events:
- Retirement (work stoppage) or significant reduction in work hours (work reduction)
- Marriage
- Divorce or annulment
- Death of a spouse
- Loss of income-producing property due to a disaster or other event beyond the individual's control
- Loss of pension income due to termination or reorganization
- Employer settlement payment received in the base year that inflated reported income
Voluntary income reductions, such as deciding to draw less from investment accounts in a given year, generally do not qualify as life-changing events for SSA-44 purposes. A Roth conversion is a voluntary income event; if it pushed MAGI above a threshold in the lookback year, an SSA-44 appeal based on lower current income is only available if a separate qualifying life event has also reduced income.
How the Appeal Works
When an appeal is approved, SSA recalculates the IRMAA tier using the more recent income (or current-year estimate) and adjusts premiums prospectively. The adjustment does not generally result in retroactive refunds for premiums already paid; it applies going forward once processed.
Submitting SSA-44 requires documentation: a statement of the qualifying event, relevant supporting documentation (retirement letter, death certificate, divorce decree, etc.), and income information for the more recent year. The form and instructions are available through the SSA.
How IRMAA Stacks on Other Planning Variables
IRMAA does not operate in isolation. It shares the same MAGI calculation with other income-related thresholds in retirement; multiple consequences can activate simultaneously from a single income event.
The Social Security Tax Torpedo. As described separately on this site, the torpedo occurs when additional income causes more Social Security benefits to phase into taxable income, creating an elevated effective marginal rate. An income increase that fires the torpedo and simultaneously crosses an IRMAA threshold two years later compounds the cost of that income: the torpedo effect applies in the year the income is received, and the IRMAA surcharge applies in the second year after. Taken together, a Roth conversion or IRA distribution that crosses both thresholds carries a multi-year total cost substantially higher than the nominal income tax in the conversion year alone. See The Social Security Tax Torpedo for detail on that interaction.
Net Investment Income Tax. The 3.8% Net Investment Income Tax (NIIT) applies to net investment income for taxpayers above a MAGI threshold ($200,000 single, $250,000 MFJ as of the date this article was written). A large asset sale or Roth conversion that raises MAGI above those lines can simultaneously trigger the NIIT on investment income that would not otherwise be subject to it.
State Income Taxes. IRMAA is a federal Medicare surcharge with no state counterpart. However, the income event that triggers IRMAA, such as an IRA distribution, capital gain, or Roth conversion, is generally taxable at the state level in most states. California, for example, taxes IRA distributions as ordinary income and provides no exclusion for retirement income, meaning the full federal and state income tax applies to the same distribution that activates IRMAA two years later.
What Coordinated Planning Addresses
Managing IRMAA effectively requires knowing, in advance, where MAGI is projected to land in each year, and mapping that figure against the tier thresholds for the year two years later.
For retirees executing multi-year Roth conversion strategies, this means modeling not just the income tax on each year's conversion but the IRMAA tier that conversion will produce in years two and three. A conversion that appears efficient from a bracket perspective may not be efficient when IRMAA surcharges are included in the total cost calculation.
For retirees approaching RMD age with large IRA balances, projecting the IRMAA tier at age 73 (or later, if SECURE 2.0 provisions apply) based on current account growth assumptions provides a long-range estimate of Medicare costs that should inform the pace of pre-RMD conversions.
For retirees who experience a qualifying life event that reduces income, an SSA-44 appeal is worth evaluating promptly: premium adjustments apply prospectively once processed, and delays reduce the benefit of the adjustment.
The variable most easily misunderstood is the cliff structure. The goal is not simply to minimize income; it is to maintain income in the correct tier relative to planning objectives. A retiree who converts too little each year to stay below a threshold may carry a larger future RMD burden than a retiree who accepts a higher tier in exchange for a significantly reduced future RMD, depending on the account balance, return assumptions, life expectancy, and other income sources. There is no universal answer; the right amount depends on the full picture.
Related Reading
- The Social Security Tax Torpedo How the Social Security benefit phase-in creates an elevated effective marginal rate, and how IRMAA surcharges can stack on top of it. Read →
- Roth IRA Conversion Strategies for High-Net-Worth Investors How partial Roth conversions can reduce future RMD exposure, and why IRMAA thresholds factor into conversion sizing decisions. Read →
- Smart Tax Strategies for Retirement A broader look at account types, withdrawal order, RMD planning, and multi-year tax projection in retirement. Read →
This post is for general educational purposes only and does not constitute tax, legal, or investment advice. Individual circumstances vary; consult a qualified tax professional, financial advisor, or Medicare specialist before making planning decisions. IRMAA surcharge amounts, premium figures, and income thresholds reflect Medicare rules published as of the date this article was written and are adjusted annually by the Centers for Medicare and Medicaid Services; verify current figures with CMS, SSA, or a qualified professional. References to SECURE 2.0 RMD age provisions reflect the law as written at the time of publication; consult a qualified professional for the applicable rules in your situation. The hypothetical illustrations in this post are simplified and do not represent the experience or results of any actual individual.