IRMAA (the Income-Related Monthly Adjustment Amount) is an extra charge added to your Medicare Part B and Part D premiums when your income is above a set level. It is based on your modified adjusted gross income (MAGI) from your tax return two years earlier.
Medicare uses your modified adjusted gross income: your adjusted gross income plus any tax-exempt interest. Social Security looks at the most recent tax return on file, which runs two years behind, so your 2024 return sets your 2026 premium. If your income is above the first bracket, a surcharge is added on top of the standard Part B premium ($202.90 a month in 2026) and on top of your Part D plan premium.
The brackets work as cliffs rather than a gradual slope. Going a single dollar over a threshold moves your whole surcharge up to the next tier for the entire year, which is why people near a line watch their income closely.
| 2024 income (MAGI) | Part B / mo | Part D / mo |
|---|---|---|
| $109,000 or less | $202.90 | $0.00 |
| $109,001 – $137,000 | $284.10 | +$14.50 |
| $137,001 – $171,000 | $405.80 | +$37.50 |
| $171,001 – $205,000 | $527.50 | +$60.40 |
| $205,001 – $499,999 | $649.20 | +$83.30 |
| $500,000 or more | $689.90 | +$91.00 |
Source: official 2026 Medicare amounts (CMS / SSA). Part D IRMAA amounts are the published 2026 SSA figures. Last verified June 2026.
Single filers cross the first bracket at $109,000 and married couples filing jointly at $218,000. Married filing separately is treated harshly: the surcharge starts at $109,000 and jumps quickly, with only three tiers.
Because of the two-year lookback, a recent retirement or other life event can leave you paying on income you no longer earn. If a qualifying event lowered your income, you can ask Social Security to use newer figures with Form SSA-44. If you are simply close to a bracket, see how to stay under the next one.