Medicare's IRMAA surcharge for 2028 will be based on your 2026 income, not your 2028 income, because IRMAA uses a 2-year lookback. Since the 2026 tax year is not yet complete, the 2028 brackets are still projections, not official numbers. Based on confirmed 2026 brackets and expected inflation trends, the 2028 single-filer threshold is likely to land between $113,000 and $117,000, with the married filing jointly threshold between $226,000 and $234,000. The Social Security Administration will not confirm the actual 2028 brackets until late 2027, after the September 2026 through August 2027 CPI-U data is finalized.
If you are planning ahead, whether you are approaching Medicare eligibility, managing a Roth conversion, or timing a large capital gain, understanding how the lookback works and where the brackets are headed can help you avoid an unexpected premium jump two years from now.
What Is IRMAA and Why the 2-Year Lookback Matters
IRMAA stands for Income-Related Monthly Adjustment Amount. It is a surcharge added to your standard Medicare Part B and Part D premiums if your Modified Adjusted Gross Income (MAGI) exceeds certain thresholds. MAGI for IRMAA purposes is your Adjusted Gross Income plus tax-exempt interest income, such as interest from municipal bonds.
The Social Security Administration does not use your current income to set your current premium. Instead, it looks back two full tax years. Your 2026 Medicare premium is based on the tax return you filed for 2024 income. Your 2028 premium will be based on the tax return you file for 2026 income, which most people won't submit until spring 2027.
This lag is the reason IRMAA catches people off guard. A retiree who sells a rental property or takes a large IRA distribution in 2026 may not see the premium impact until January 2028, long after the income event is behind them. By the time the surcharge notice arrives, the income decision has already been made and can't be undone.
IRMAA operates as a cliff, not a gradual scale. Crossing a threshold by even one dollar triggers the entire next tier's surcharge for that year, not just a surcharge on the amount over the line. This makes precise income planning valuable in the two years before a Medicare enrollment or premium reset.
Confirmed 2026 IRMAA Brackets (Based on 2024 Income)
These are the official, confirmed IRMAA brackets in effect for 2026. The standard Part B premium in 2026 is $202.90 per month.
| MAGI, Single Filer | MAGI, Married Filing Jointly | Part B Surcharge | Total Monthly Part B Premium |
|---|
| $109,000 or less | $218,000 or less | None | $202.90 |
| $109,001 to $137,000 | $218,001 to $274,000 | 40% increase | approximately $284.10 |
| $137,001 to $171,000 | $274,001 to $342,000 | 100% increase | approximately $405.80 |
| $171,001 to $205,000 | $342,001 to $410,000 | 160% increase | approximately $527.50 |
| $205,001 to $499,999 | $410,001 to $749,999 | 220% increase | approximately $649.30 |
| $500,000 or more | $750,000 or more | 240% increase | approximately $690.10 |
Part D IRMAA surcharges apply on top of your plan's premium and range from approximately $14.50 to $90.40 per month across the same income tiers.
Projected 2027 IRMAA Brackets (Based on 2025 Income)
The 2027 brackets are not yet finalized because they depend on CPI-U data through August 2026, which is not fully available. Based on partial 2026 inflation data, analysts project the following ranges, shown at 0% and 3% annualized inflation for the remaining uncollected months.
| MAGI, Single Filer (0% to 3% inflation) | MAGI, Married Filing Jointly (0% to 3% inflation) |
|---|
| $112,000 to $113,000 | $224,000 to $226,000 |
| $141,000 to $143,000 | $282,000 to $286,000 |
| $176,000 to $179,000 | $352,000 to $358,000 |
| $211,000 to $215,000 | $422,000 to $430,000 |
| approximately $500,000 (top tier unchanged historically) | approximately $750,000 |
Projected 2028 IRMAA Brackets (Based on 2026 Income)
The 2028 brackets are the least certain, since they depend on 2026 income data and CPI-U figures that will not be complete until August 2027. These figures are preliminary estimates built from historical CPI-U trends of roughly 2% to 3% annual growth applied on top of the projected 2027 brackets.
| MAGI, Single Filer (0% to 3% inflation) | MAGI, Married Filing Jointly (0% to 3% inflation) | Estimated Part B Surcharge |
|---|
| $114,000 to $117,000 | $226,000 to $234,000 | None |
| $143,000 to $147,000 | $286,000 to $294,000 | 40% increase |
| $179,000 to $184,000 | $358,000 to $368,000 | 100% increase |
| $214,000 to $220,000 | $430,000 to $440,000 | 160% increase |
| approximately $507,000 to $517,000 | approximately $760,000 to $775,000 | 220% increase |
| above the prior tier | above the prior tier | 240% increase |
Treat every number in the 2028 table as a planning estimate, not a fact you can rely on for a final decision. The Centers for Medicare and Medicaid Services (CMS) will not publish official 2028 brackets until late 2027, typically in the same announcement as the standard Part B premium for that year.
How the Bracket Projections Are Calculated
IRMAA brackets are indexed to inflation using a specific CPI-U formula: the average of the 12 monthly CPI-U readings ending in August of the prior year, compared against the average CPI-U for the same 12-month period one year earlier. This is different from the CPI-W formula used for the annual Social Security cost-of-living adjustment, which is why IRMAA brackets and Social Security COLA percentages rarely match exactly.
A useful detail for planning: even in a hypothetical year with 0% forward inflation, IRMAA brackets in 2027 and 2028 are still projected to rise, because prior years' price increases remain baked into the rolling 12-month average used in the formula. This is why every published projection shows two scenarios, a low-inflation case and a higher, 3% case, rather than one flat number.
Why This Matters for Income Planning
Because of the 2-year lookback, decisions made in 2026 will not show up as a premium surcharge until your Medicare bill in January 2028. Common income events that push people into a higher IRMAA tier include:
- Converting a traditional IRA to a Roth IRA
- Selling a home, rental property, or other appreciated asset
- Taking a large required minimum distribution (RMD)
- A one-time bonus, severance package, or business sale
- Municipal bond interest, which counts toward MAGI even though it's federally tax-exempt
If you know you have a high-income year coming up in 2026 or 2027, it can help to model where that income lands relative to the projected bracket thresholds above, well before the SSA notice arrives two years later.
How to Appeal or Adjust an IRMAA Determination
If a life-changing event reduced your income after the lookback year, such as retirement, divorce, or the death of a spouse, you can file Form SSA-44 to request a reconsideration using more current income instead of the 2-year-old tax return. Qualifying life events include:
- Marriage, divorce, or death of a spouse
- Work stoppage or reduction in work hours
- Loss of income-producing property due to a disaster or other event beyond your control
- Loss or reduction of pension income
- An employer settlement payment tied to closure or bankruptcy
If your MAGI simply changed due to a one-time capital gain or Roth conversion, none of these events apply, and the standard 2-year lookback stands regardless of how temporary the income spike was.
Frequently Asked Questions
When will the official 2028 IRMAA brackets be released?
CMS typically announces the official brackets for a given year in the fall of the prior year, alongside the standard Part B premium announcement. Expect official 2028 numbers around November 2027, based on the pattern from prior years.
What income year determines my 2028 Medicare premium?
Your 2028 Medicare Part B and Part D premiums, including any IRMAA surcharge, will be based on your Modified Adjusted Gross Income reported on your 2026 tax return, the one you file in early 2027.
Can I estimate my 2028 IRMAA bracket now?
You can get a reasonable estimate by comparing your projected 2026 MAGI against the ranges in the 2028 table above. Because the final CPI-U data isn't in yet, treat the estimate as a planning guide, not a guarantee, and revisit it once official numbers are published in late 2027.
Does IRMAA apply to both Part B and Part D?
Yes. IRMAA adds a surcharge to both your Part B premium and your Part D premium (or the Part D portion of a Medicare Advantage plan with drug coverage) if your MAGI exceeds the threshold. The two surcharges are billed separately but both use the same income brackets.
Is there a way to avoid an IRMAA surcharge entirely?
The only way to avoid IRMAA is to keep your MAGI under the lowest threshold in the year that will be used for the lookback. Because the lookback is fixed at two years, spreading out large income events like Roth conversions across multiple years, rather than realizing them all at once, is one of the more common strategies advisors use to manage which bracket a retiree lands in.
What counts as income for IRMAA purposes?
IRMAA uses MAGI, which includes your Adjusted Gross Income plus tax-exempt interest, such as interest from municipal bonds. It includes wages, taxable Social Security benefits, pension income, taxable IRA and 401(k) withdrawals, capital gains, rental income, and dividends. It does not include the value of your home or unrealized gains on investments you haven't sold.
Will my IRMAA surcharge go down if my income drops after a high-income year?
Yes, but only after the 2-year lookback catches up. If your 2026 income is high and then drops significantly in 2027, your 2028 premium (based on 2026 income) will still reflect the higher bracket. Your 2029 premium would then reflect the lower 2027 income, unless you qualify for a life-changing event exception under Form SSA-44.
