IRMAA Explained: How Retirement Income Triggers Medicare Surcharges — and How to Plan Around Them

What IRMAA Actually Is

IRMAA stands for Income-Related Monthly Adjustment Amount. It is not a penalty — it is simply a higher Medicare premium charged to beneficiaries whose income exceeds certain thresholds. Congress introduced it in 2003 as a way to have higher-income Medicare enrollees pay a larger share of the program's cost.

IRMAA applies to Medicare Part B (medical insurance) and Medicare Part D (prescription drug coverage). It does not affect Part A (hospital insurance) premiums, which are generally $0 for most beneficiaries who have worked 40+ quarters.

In 2025, the standard Part B premium is $185.00 per month per person. At the highest IRMAA tier, that number jumps to roughly $628.90 per month — an increase of more than $5,300 per year per person. For a couple where both spouses are on Medicare, the highest tier adds over $10,600 per year in extra healthcare costs.

2025 IRMAA Brackets: Part B and Part D

Individual MAGI	Joint MAGI	Part B Monthly Premium	Part D Monthly Surcharge
≤ $106,000	≤ $212,000	$185.00 (standard)	$0 (plan premium only)
$106,001–$133,000	$212,001–$266,000	~$259.00	~$13.70
$133,001–$167,000	$266,001–$334,000	~$370.00	~$35.30
$167,001–$200,000	$334,001–$400,000	~$480.90	~$57.00
$200,001–$500,000	$400,001–$750,000	~$591.90	~$78.60
Over $500,000	Over $750,000	~$628.90	~$85.80

Note: Thresholds adjust annually for inflation. Part D surcharges are added on top of your plan's regular premium. Verify current figures at Medicare.gov.

The Two-Year Look-Back: Why This Catches Retirees Off Guard

The most important and least understood feature of IRMAA is its timing. Medicare does not set your premium based on this year's income — it uses the most recent tax return available when premiums are set, which is typically from two years prior. Your 2025 Medicare premium is based on your 2023 MAGI.

This creates a planning lag with real consequences. A retiree who took a large IRA distribution in 2023 — perhaps to fund a home renovation or a one-time expense — may see elevated Medicare premiums throughout all of 2025 and have no way to undo it. The decision and the consequence are separated by two full years.

What Counts as MAGI for IRMAA?

IRMAA is based on your Modified Adjusted Gross Income (MAGI), which for Medicare purposes is your AGI plus any tax-exempt interest income (such as municipal bond interest). Understanding precisely what is included helps you model the real impact of income decisions.

Income Sources That Count Toward IRMAA MAGI

• Traditional IRA and 401(k) withdrawals: Every dollar you take from a pre-tax retirement account is fully included in MAGI. This is the most common trigger for retirees crossing IRMAA thresholds.
• Required Minimum Distributions (RMDs): RMDs are ordinary income and count dollar-for-dollar. Once RMDs begin at age 73, they can push income well above IRMAA thresholds, especially for retirees with large traditional IRA balances.
• Social Security benefits (taxable portion): Up to 85% of your Social Security benefit may be included in gross income depending on your combined income. That taxable portion is part of your MAGI.
• Capital gains and qualified dividends: All realized capital gains (short and long-term) and dividends are included. Selling a large appreciated position in a single year is a common accidental IRMAA trigger.
• Pension and annuity income: Taxable pension distributions and the taxable portion of annuity payments count toward MAGI.
• Rental income: Net rental income from real estate is included.
• Business income: Self-employment or business income counts in full.
• Tax-exempt interest: Interest from municipal bonds is added back to AGI to compute MAGI for IRMAA purposes — a detail that often surprises retirees holding large muni bond portfolios.
• Roth conversions: The amount converted from a traditional IRA to a Roth IRA is ordinary income in the year of conversion and is fully included in MAGI.

Income Sources That Do NOT Count Toward IRMAA MAGI

• Roth IRA distributions: Qualified Roth withdrawals are completely tax-free and do not appear on your tax return — no MAGI impact whatsoever. This is one of the primary long-term benefits of Roth accounts in retirement.
• Health Savings Account (HSA) distributions for qualified medical expenses: Tax-free HSA withdrawals for medical expenses do not count.
• Life insurance death benefits: Proceeds received as a beneficiary are generally not included in income.
• Return of principal from non-qualified annuities: The portion of an annuity payment that is a return of your original after-tax investment (the exclusion ratio) is not income.
• Reverse mortgage proceeds: Loan proceeds from a reverse mortgage are not income.
• Gifts received: Amounts received as gifts are not income to the recipient.

The Cliff Effect: Why One Dollar Matters

IRMAA operates as a step function, not a gradual curve. Crossing a threshold by $1 moves you into an entirely new tier. If your MAGI is $106,000 as an individual, you pay the standard Part B premium of $185/month. If it is $106,001, you pay approximately $259/month — an increase of $74/month or $888/year from a single dollar of additional income.

For married couples filing jointly, the same cliff effect applies at $212,000: one dollar over the threshold adds $888 per person, or $1,776 per year for the couple. At higher tiers, the jumps are even larger.

This asymmetry makes precision planning valuable. Calibrating income to stay just below a threshold — even if it means taking slightly less from a retirement account than you originally intended — can pay off substantially over a year of Medicare premiums.

Planning Strategies to Manage IRMAA

1. Manage Roth Conversion Size Annually

Roth conversions are one of the largest variables a retiree can control year to year. Sizing conversions to stop just below an IRMAA threshold — accounting for all other expected income — keeps Medicare premiums at the standard rate. If crossing a tier is necessary, convert to the top of that tier rather than barely over it, capturing more tax-free growth for the same one-year premium cost.

2. Use Roth Accounts Strategically in High-Income Years

In years when other income is unusually high (a large capital gain, an inheritance, a RMD spike), drawing from Roth accounts rather than traditional IRAs keeps MAGI flat. Roth withdrawals are invisible to IRMAA. Accumulating a meaningful Roth balance specifically for use in high-income years is a deliberate IRMAA management strategy.

3. Control Capital Gain Realization Timing

If you plan to sell appreciated securities, spreading the sale across two or three tax years rather than all in one year can keep annual MAGI below the next IRMAA tier. Tax-loss harvesting can also offset gains in the current year to reduce MAGI.

4. Delay Social Security to Reduce Early MAGI

While delaying Social Security increases the eventual benefit, the taxable portion of Social Security income also raises MAGI once benefits begin. In the years before Social Security starts — and before RMDs begin — income is often at its lowest, creating a window for Roth conversions or capital gain realization at lower tax cost and potentially below IRMAA thresholds.

5. Qualified Charitable Distributions (QCDs)

If you are age 70½ or older and donate to charity, using a Qualified Charitable Distribution from your IRA satisfies the RMD requirement without the funds appearing in your gross income. A $20,000 QCD reduces AGI and MAGI by $20,000 compared to taking the RMD as cash and writing a check to charity — a meaningful IRMAA management tool for charitably inclined retirees.

6. Front-Load Conversions Before Age 63

Because Medicare premiums at age 65 are based on income at age 63, large Roth conversions executed before age 63 do not affect Medicare premiums. Conversions at 60, 61, and 62 may create a tax bill in those years, but leave no IRMAA footprint at Medicare enrollment. This is especially powerful for retirees who leave the workforce early and have a low-income window before age 63.

7. Appeal After a Life-Changing Event (Form SSA-44)

If your income has dropped significantly since the tax year Medicare is using — due to retirement, loss of a spouse, divorce, or reduction in work — you can file Form SSA-44 with the Social Security Administration. The SSA may adjust your IRMAA based on more recent income rather than the two-year-old figure. This appeal is not automatic; you must initiate it and provide documentation of the income change.