IRMAA Brackets 2028: Estimate Based on 2026 Income
Not published yet. CMS has not announced the 2028 IRMAA brackets, and the inflation data that sets them does not exist until after August 2027. Your 2026 income decides your 2028 bracket, so this page lets you test an inflation assumption and see what the statute would produce.
Maintained by Archie Chang · Scenario computed from statute and BLS data October 23, 2026 · Methodology & sources
Status: 2028 brackets are not out
CMS publishes IRMAA thresholds and premiums for a year in the fall before it starts, usually in November. The 2027 figures are expected this November, and the 2028 figures a year later, in fall 2027. Until then every 2028 number is an estimate. The four lower thresholds depend on the average CPI-U for September 2026 through August 2027. BLS has published CPI-U through September 2026 (336.940), so eleven months of that window are still ahead.
For the premium itself, the 2026 Medicare Trustees Report projects a standard 2028 Part B premium of $224.50 (a projection, Table V.E2). We do not estimate 2028 IRMAA dollar amounts, because CMS sets them with its own cost figures.
IRMAA 2028 estimator (2026 income)
Enter the average yearly CPI-U inflation rate you want to assume from October 2026 through August 2027. September 2026 is the actual BLS value; the other months grow from it at your rate. The result is a scenario, not an official or forecast figure.
| Threshold (2026 MAGI) | Single / individual | Married filing jointly |
|---|---|---|
| First bracket starts above | $117,000 | $234,000 |
| Second bracket starts above | $147,000 | $294,000 |
| Third bracket starts above | $183,000 | $366,000 |
| Fourth bracket starts above | $220,000 | $440,000 |
| Top bracket starts at | $520,000 | $780,000 |
Married filing separately (lived with spouse during the year): IRMAA starts above $117,000, and the top bracket starts at $403,000. Average CPI-U in the window ending August 2027 at this assumption: 342.616, against 329.656 for the 12 months ending August 2026.
The default of 3.7% is an assumption, not a forecast: it is the latest 12-month CPI-U change BLS has published (September 2026 336.940 versus September 2025 324.800, retrieved October 23, 2026 from BLS series CUUR0000SA0).
How much the assumption matters
Single-filer thresholds for 2028 under five inflation assumptions. Joint thresholds are twice these, except the top one, which is 150% of the individual top.
| Threshold (2026 MAGI) | 2% a year | 2.5% a year | 3% a year | 3.5% a year | 4% a year |
|---|---|---|---|---|---|
| First bracket starts above | $116,000 | $116,000 | $116,000 | $117,000 | $117,000 |
| Second bracket starts above | $146,000 | $146,000 | $147,000 | $147,000 | $147,000 |
| Third bracket starts above | $182,000 | $183,000 | $183,000 | $183,000 | $184,000 |
| Fourth bracket starts above | $218,000 | $219,000 | $219,000 | $220,000 | $220,000 |
| Top bracket starts at | $516,000 | $517,000 | $518,000 | $519,000 | $520,000 |
| Joint: first bracket above | $232,000 | $232,000 | $232,000 | $234,000 | $234,000 |
Across 2% to 4%, the first threshold moves by $1,000 and the top threshold by $4,000.
How the formula works
Under 42 U.S.C. 1395r(i), the four lower thresholds start from $85,000, $107,000, $133,500 and $160,000. Each is multiplied by the percentage by which average CPI-U for the 12 months ending August of the preceding year exceeds the average for the 12 months ending August 2018, then rounded to the nearest $1,000. For 2028 the window is September 2026 to August 2027. Joint-return thresholds are twice the individual ones. The same method reproduces every official threshold from 2021 to 2026; our IRMAA brackets 2027 page shows the back-test.
The top threshold changes in 2028. Through 2027 the $500,000 individual and $750,000 joint levels are fixed. Paragraph (5)(C)(ii) says that for any calendar year beginning after 2027 the $500,000 amount is increased by that amount multiplied by the percentage, if any, by which the average CPI-U for the 12 months ending August of the preceding year exceeds the average for the 12 months ending August 2026. The base is therefore a recent year, not 2018, so the top threshold grows far less than the lower ones. We use the published months of that base period; BLS did not publish October 2025, and filling it in with the average of its neighbors moves the rounded individual top threshold by up to $1,000 (up to $1,500 for joint returns) in the table above. If prices fall, the top threshold stays at $500,000; it is never reduced. The joint top level is 150 percent of the rounded individual one, which can end in $500; CMS has not applied this rule yet and could round the joint amount differently.
Married people who file separately and lived with their spouse at any time in the year have the statutory amounts reduced by the unmarried threshold. In practice, IRMAA starts above the first threshold and the top bracket starts at the top threshold minus the first threshold.
What 2026 income counts
Social Security uses modified adjusted gross income (MAGI) from your 2026 federal return: adjusted gross income plus tax-exempt interest, with certain excluded foreign and U.S.-territory income and savings bond interest added back. That means more than wages or Social Security.
- A Roth conversion in 2026 raises AGI by the taxable amount converted.
- Capital gains from selling stock, a home above the exclusion, or a business count in the year of the sale.
- Required minimum distributions and other pension or IRA withdrawals count.
- Tax-exempt municipal bond interest is added back even though it is not taxed.
One dollar over a threshold moves you into the next bracket for the whole year, so the cliff matters more than the average. If a life-changing event lowers your income, such as retirement, a work reduction, marriage, divorce, the death of a spouse or a loss of income-producing property, you can ask SSA to use a more recent year with Form SSA-44. See SSA's Medicare premiums page for the events it accepts.
Comparison with 2026 and 2027
| Individual threshold | 2026 (official, 2024 income) | 2027 (computed, 2025 income) | 2028 (3.7% scenario, 2026 income) |
|---|---|---|---|
| First bracket starts above | $109,000 | $112,000 | $117,000 |
| Second bracket starts above | $137,000 | $142,000 | $147,000 |
| Third bracket starts above | $171,000 | $177,000 | $183,000 |
| Fourth bracket starts above | $205,000 | $212,000 | $220,000 |
| Top bracket starts at | $500,000 | $500,000 | $520,000 |
2027 uses the 11 published months of the 12 ending August 2026; some middle thresholds could be $1,000 lower if CMS treats the missing October 2025 index differently. Official 2026 figures are on IRMAA brackets 2026. To test your own income against a bracket, use the IRMAA calculator.
IRMAA 2028 questions
What are the IRMAA brackets for 2028?
They are not published yet. CMS usually announces each year's thresholds in the fall before the premium year, so 2028 is expected in fall 2027. As a scenario, assuming 2% to 4% yearly CPI-U inflation from October 2026 to August 2027, the first bracket would start above about $116,000 to $117,000 of 2026 income for single filers and $232,000 to $234,000 for joint filers. These are estimates from a formula, not CMS figures.
Which income is used for 2028 IRMAA?
Your 2026 tax return. Social Security looks back two years, so 2028 premiums are based on 2026 modified adjusted gross income. If the IRS does not have your 2026 return yet when SSA decides, SSA can use 2025 data and correct it later.
Why can you not calculate the 2028 thresholds exactly yet?
The law indexes them to the average CPI-U for September 2026 through August 2027. BLS has published only through September 2026 (336.940), so eleven months are still unknown. The page lets you assume an inflation rate for them.
Does the $500,000 top threshold change in 2028?
Yes. Until 2027 the $500,000 individual and $750,000 joint levels are fixed. For calendar years after 2027 the statute indexes the $500,000 amount to CPI-U, measured against the 12 months ending August 2026 rather than August 2018. The joint level is 150 percent of the individual level.
What will the 2028 Part B premium be?
Unknown. The 2026 Medicare Trustees Report projects a standard 2028 Part B premium of $224.50 and a $313 deductible (Table V.E2, intermediate assumptions). That is a projection, and we do not compute 2028 IRMAA dollar amounts. CMS sets them with the 2028 announcement.
Can I appeal if my income dropped after 2026?
If a life-changing event such as retirement, marriage, divorce, the death of a spouse or the loss of income-producing property reduced your income, you can ask SSA to use a more recent year with Form SSA-44. Voluntary choices that raised 2026 income, such as a Roth conversion, are generally not accepted as a reason.
IRMAA by year and tools
Authoritative sources: 42 U.S.C. 1395r(i) · BLS: CPI-U (CUUR0000SA0) · 2026 Medicare Trustees Report · SSA: Form SSA-44