Understanding the IRMAA Two-Year Look-Back Rule
Understanding the IRMAA Two-Year Look-Back Rule and how income from two years ago can increase Medicare Part B and Part D premiums for retirees.
Imagine retiring at 63 after decades of working and then receiving your first Medicare bill at 65 for $649.20 per month in Part B premiums, per person.
Not because of what you're earning in retirement, but because of what you earned two years earlier.
That's the IRMAA two-year look-back rule, and it's one of the Medicare surprises that can catch new retirees off guard.
If you're in your early 60s, this matters now. The income you report before Medicare begins can affect what you pay for Medicare two years later. And in some situations, if your income drops after retirement, you may be able to ask Social Security to use more recent income instead.
What Is the IRMAA Two-Year Look-Back Rule?
The IRMAA two-year look-back rule means Social Security generally uses your income from two years earlier to determine whether you'll pay higher Medicare Part B and Part D premiums.
For example:
2024 income → 2026 Medicare premiums
2025 income → 2027 Medicare premiums
2026 income → 2028 Medicare premiums
More specifically, Social Security looks at your Modified Adjusted Gross Income, or MAGI, from the applicable federal tax return.
There is an important exception: if certain life-changing events cause your income to drop, such as retirement or a reduction in work, you may be able to request a new determination using more recent income.
Want to see what your own income means in real dollars? The 2026 IRMAA calculator shows the Part B and Part D surcharge for each bracket.
Why the IRS and Social Security Use Old Tax Data
The two-year lag exists for a practical reason: Social Security needs a completed tax return to determine your income. When Medicare premiums are set for a given year, the most recent complete federal tax returns are typically those filed the previous April, covering income from two years prior. Social Security cannot use "this year's income" because that return has not been filed yet.
In practice, the Social Security Administration uses data shared by the Internal Revenue Service under a formal data-sharing agreement. According to the Social Security Administration, when SSA does not have your most recent tax data available, they may use the return from three years prior — making the look-back problem potentially even worse in some edge cases.
The Year-by-Year Mechanics: A Clear Example
To make the look-back concrete, here is how it works for someone who retires at 65 in 2026:
Year Activity - Income Used for IRMAA?
2024 Final full year of work — MAGI: $390,000 Sets 2026 Medicare premiums
2025 Retired in March — partial year income of $185,000 Sets 2027 Medicare premiums
2026 Full year in retirement — Social Security +
IRA withdrawals: $120,000 Sets 2028 Medicare premiums
2027 Full retirement — MAGI: $118,000 Sets 2029 Medicare premiums
At that income level, each person would pay $649.20 per month for Medicare Part B in 2026, plus an $83.30 monthly Part D IRMAA surcharge. For a couple, that's $1,298.40 per month in Part B premiums, plus $166.60 in combined Part D IRMAA surcharges, before the cost of their actual Part D plans. By 2028 or 2029, their premiums will normalize to reflect their actual retirement income. The additional cost can be significant. But if retirement or another qualifying life-changing event caused your income to fall, don't assume you're stuck with the original determination. You may be able to request that Social Security use more recent income.
Free Resource
Your 2026 premium was set by your 2024 income. You may be able to ask for a new determination.
If your income dropped because you retired, lost a spouse, or had a pension end, Social Security may allow a new determination using a more recent year. The IRMAA Appeal Checklist walks through the eight qualifying life events on Form SSA-44, the documentation to gather, and the date rule that catches people out.
Get the IRMAA Appeal Checklist → Free PDF, no email required.Situations That Can Create an Unexpected IRMAA Surcharge
Retiring at or Near Age 65
The classic look-back trap: your last year of W-2 income is exactly the year that sets your first Medicare premiums. If your employer pays you through December 31 of the year you turn 65, that full working-year income is the baseline.
That doesn't necessarily mean you'll be stuck paying IRMAA based on your former salary. If retirement causes your income to drop, work stoppage may qualify you to request a new determination using more recent income through Form SSA-44.
Planning ahead still matters, though. Your retirement date can affect salary, bonuses, stock compensation, capital gains, Roth conversions, and other income that ultimately flows into MAGI.
The Business Sale Problem
Selling a business or investment property often generates a one-time capital gain that can be five to ten times your normal annual income. A business owner who sells for $2 million in 2024 with a $1.5 million gain could see MAGI well above $1 million that year — triggering the maximum IRMAA tier for both 2026 and, if the business generated deferred income, potentially beyond. Unlike retirement itself, a voluntary business or investment-property sale generally isn't one of the qualifying life-changing events that allows you to simply replace the income year used by Social Security. See our guide to IRMAA appeals using Form SSA-44.
Roth Conversions Without Bracket Awareness
Roth conversions are one of the most powerful tools for retirement tax planning. But they add directly to MAGI in the year of conversion. A large Roth conversion can push MAGI across one or more IRMAA thresholds and increase Medicare premiums two years later. That's not a reason to avoid Roth conversions. It's a reason to consider the tax benefit and the potential IRMAA cost together. See the full 2026 IRMAA brackets here.
If you're considering conversions before RMDs begin, see how Roth conversion planning fits into the broader retirement tax picture.
The RMD Stack
Required Minimum Distributions begin at age 73. Once RMDs begin, you're generally required to take a minimum distribution from your tax-deferred retirement accounts each year. For retirees with large traditional IRA balances, RMDs can add tens of thousands of dollars of taxable income each year. That income stacks on top of Social Security, pensions, and any interest or dividends. For retirees who did not do Roth conversions in their 60s, RMDs can push them into an IRMAA tier and keep them there indefinitely.
This is why RMD planning, Roth conversions and Medicare premiums should be evaluated together as part of retirement tax planning.
When the Two-Year Look-Back Can Work in Your Favor
The look-back is not always punishing. A single unusually high-income year generally affects IRMAA for a single future Medicare premium year. The two-year rule describes the lag between the income year and the Medicare year; it does not mean one high-income year automatically creates two years of higher premiums.
For example, unusually high 2024 MAGI can increase 2026 premiums. If 2025 MAGI returns to a lower level, the 2027 IRMAA determination may also fall.. By year three, if your ongoing income is lower, your premiums normalize. You do not need to take action in that case; time is the remedy.
The same rule can also work in your favor. If your income was unusually low two years earlier, your Medicare premiums may reflect that lower-income year even if your income has since increased.
When Can You Override the Look-Back? Life-Changing Events
The one formal mechanism for overriding the two-year look-back is the Social Security Administration's Form SSA-44, which allows you to request that SSA use a more recent year's income if a qualifying life-changing event has reduced your income.
Qualifying life-changing events include:
Marriage
Divorce or annulment
Death of a spouse
Work stoppage
Work reduction
Loss of income-producing property under qualifying circumstances
Loss or reduction of pension income
Receipt of a qualifying employer settlement payment
Importantly, investment losses — even severe ones — do not qualify as a life-changing event for IRMAA purposes. If your portfolio dropped 30% but your MAGI did not change meaningfully, that does not trigger SSA-44 relief. Read our full guide to the IRMAA appeal process.
How the Appeal Works in Practice
If you retired in March 2025 and your 2025 income was substantially lower than your 2024 income, you can file Form SSA-44 to request that SSA use your 2025 income (or an estimate of your 2026 income) for your 2026 IRMAA determination. You will need to provide your most recent tax return and documentation of the qualifying event. SSA will review the request and, if approved, issue a new determination based on the appropriate more recent income information.
If a life event lowered your income, you may be able to request a new determination — the process is covered in How to Appeal an IRMAA Determination Using Form SSA-44.
Proactive Strategies: Planning Around the Look-Back
If you're still a few years from Medicare, there are several planning decisions worth considering before your premiums are set:
1. Understand How Your Retirement Date Changes Your Income
If you have flexibility around your retirement date, compare the income consequences before choosing one. Salary, bonuses, stock compensation, severance, capital gains, and planned Roth conversions can all make two retirement dates that are only a few months apart look very different from a tax and IRMAA perspective. Should I Retire This Year of Next? Calculator
2. Calibrate Roth Conversions to Stay Below Bracket Cliffs
The years between retirement and RMDs can create an attractive Roth conversion window because taxable income may temporarily be lower. But the right conversion amount depends on more than one threshold. Federal and state taxes, future RMDs, Social Security taxation, IRMAA, and your longer-term plan should all be considered together.
3. Use QCDs to Reduce RMD Impact
Once you reach 70½, Qualified Charitable Distributions from your IRA can satisfy part or all of your RMD without adding to your MAGI. A QCD reduces the income that flows into the IRMAA calculation. In 2026, the QCD limit is $108,000 per person.
4. Review Your Look-Back Window Every Year
The best approach is to run the IRMAA calculation every year — two years in advance — as part of your overall income planning. Each year, project your expected MAGI and compare it with the IRMAA thresholds that are known or reasonably estimated for the Medicare year that income will affect. That can help identify how much room you may have for Roth conversions, capital gains, or other discretionary income without accidentally crossing another IRMAA tier.
IRMAA Is Really an Income-Planning Issue
Medicare premiums don't exist in isolation.
A Roth conversion can affect taxes and IRMAA. Starting Social Security can change taxable income. Your retirement date can change your final year of earnings. RMDs can create income later that you may have had an opportunity to manage earlier.
That's why I think about IRMAA as part of the broader retirement-income decision, not as a separate Medicare problem.
Wondering how these decisions fit together? → Explore the Retirement Readiness Checkpoint
Frequently Asked Questions About the IRMAA Look-Back Period
Which year's income sets my 2026 Medicare premiums?
Your 2024 MAGI, as reported on your 2024 federal income tax return and shared by the IRS with the Social Security Administration, determines your 2026 IRMAA status and premiums.
What if I did not file a 2024 tax return?
If Social Security cannot locate your 2024 return, they will use the most recent return available — potentially your 2023 return. If that return also shows elevated income, your premiums could reflect a higher bracket. If no return is on file, SSA may use their own determination, which you can challenge.
I retired in 2025. Will my 2026 premiums still be based on my 2024 working income?
Yes, initially. However, if you retired in 2025 and your income dropped significantly, you can file Form SSA-44 to request that SSA use your 2025 income or a 2026 income estimate instead. You will need to provide evidence of the retirement and an estimate of your reduced income.
Does the look-back apply to Medicare Advantage enrollees?
Yes. The IRMAA look-back applies to all Medicare Part B enrollees regardless of whether they are in Original Medicare or a Medicare Advantage plan. It also applies to Part D enrollees regardless of drug plan type.
What happens if my 2024 return was amended after IRMAA was already determined?
If you file an amended return that reduces your MAGI below an IRMAA threshold, you can notify SSA and provide the amended return. SSA can recalculate your IRMAA based on the corrected income figures.
Are Social Security benefits included in MAGI for IRMAA?
The taxable portion of your Social Security benefits is included in your AGI, and AGI is part of MAGI. However, Social Security benefits that are not taxable (below the thresholds under IRS provisional income rules) are not included.
The Best Time to Understand the Look-Back Is Before Medicare Begins
If you're in your early 60s, the important takeaway isn't simply to avoid IRMAA. It's to understand which financial decisions affect your future Medicare premiums while you still have time to plan around them.
Sometimes paying IRMAA may be perfectly reasonable if another decision, such as a Roth conversion, produces a larger long-term benefit. The goal is to understand the trade-off before you make the decision.
Want to go deeper on IRMAA?
→ Complete IRMAA Planning Guide
Wondering how this fits your retirement?
→ Retirement Readiness Checkpoint
Hi, I'm Patrick.
I'm Patrick Thompson, founder of Sentient Financial. I'm a fee-only fiduciary financial advisor based in Laguna Niguel, serving pre-retirees throughout South Orange County and virtually across the country.
I work primarily with people approaching retirement, helping them coordinate their investments, income, taxes, Social Security, and Medicare so each decision works as part of a broader retirement plan.
If you're approaching Medicare and aren't sure how your retirement date, Roth conversions, withdrawals, Social Security, and future RMDs fit together, that's exactly the type of issue we can talk through.
I offer a complimentary 20-minute Retirement Fit Call to learn what you're trying to solve and determine whether my planning approach is a good fit for what you need.
Keep Exploring IRMAA
Think your current premium may be based on income that no longer reflects your situation?
Open the IRMAA Appeal Checklist →
Want to see what your income means for 2026 Medicare premiums?
Run the 2026 IRMAA Calculator →
Want the full planning picture?
Read the Complete IRMAA Planning Guide →
Sentient Financial, LLC is a state-registered investment adviser in California. This information is for educational purposes only and does not constitute investment, tax, or legal advice. Nothing here should be taken as a recommendation to buy or sell securities or to implement a specific strategy. Past performance does not guarantee future results. IRMAA figures are for the 2026 benefit year as published by the Centers for Medicare & Medicaid Services.
