2026 IRMAA Brackets, in Plain English
Six income brackets, two parts of Medicare, one tax return from two years ago. Here is exactly what crossing each line costs you in 2026.
IRMAA stands for Income-Related Monthly Adjustment Amount. It is the surcharge Medicare adds to your Part B and Part D premiums when your income crosses one of six brackets. CMS announced the 2026 numbers in November 2025, and they are the first thing every retiree should learn before doing any tax planning around Medicare.
How the lookback works
CMS uses your modified adjusted gross income (MAGI) from two years ago to set your premium for the current year. Your 2026 Part B and Part D premiums are decided by what you reported on your 2024 tax return. If your income spiked in 2024 because of a Roth conversion, capital gains, or a big bonus, you pay the 2026 IRMAA surcharge even if your 2026 income is lower.
The six brackets
Tier 0 covers MAGI up to $108,000 single or $216,000 joint. You pay only the standard Part B premium, $206.50 per month, plus your Part D plan with no surcharge. Tier 1 starts at $108,001 single or $216,001 joint and adds $74.10 to Part B and $14.10 to Part D. The brackets continue up through Tier 5, which starts at $497,001 single or $754,001 joint and adds $444.90 to Part B and $88.30 to Part D.
The cliff effect
IRMAA is a cliff, not a phase-in. Cross a bracket by one dollar and you pay the full surcharge for the entire year. A retiree with $216,001 of MAGI pays the same Tier 1 surcharge as a retiree with $269,000. This makes year-end MAGI management around bracket thresholds extremely valuable. A small Roth conversion can push you over a line and cost a couple $1,800 a year for two beneficiaries.
Married filing separately
The IRMAA brackets for married filing separately are aggressive: Tier 4 starts at $106,001 of MAGI and Tier 5 starts at $412,001. There is no Tier 1 through Tier 3 for separate filers. CMS treats this filing status as a high-income flag.
What does not count toward MAGI
Roth IRA distributions, HSA contributions and qualified withdrawals, life insurance proceeds, and the non-taxable portion of Social Security are excluded. This is why HSA-funded retirees and Roth-heavy retirees often stay in Tier 0 even with healthy spending.
Appealing IRMAA after a life event
If your income dropped in 2025 or 2026 because of marriage, divorce, death of a spouse, work stoppage, work reduction, loss of pension, or loss of income-producing property, you can file Form SSA-44 to ask SSA to use a more recent year. The form has a checkbox for each qualifying event and SSA approves the recalc fairly readily when documentation is clean.
Plan ahead, not after
Because of the two-year lookback, the time to manage IRMAA is the year before you turn 63. If you wait until 65 to think about it, you have already locked in your first two years of Medicare premiums.