What is IRMAA?
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 threshold. Most people pay only the standard premium, but higher-income retirees pay a surcharge on top. The Social Security Administration decides who owes IRMAA by looking at your tax return from two years earlier. That means your 2026 surcharge is based on the income you reported for 2024.
The figure that matters is your Modified Adjusted Gross Income (MAGI). For IRMAA, MAGI is your Adjusted Gross Income (line 11 of Form 1040) plus any tax-exempt interest (line 2a) — for example, interest from municipal bonds. This add-back catches many retirees by surprise, because tax-free interest still counts toward IRMAA.
Why IRMAA is a "cliff," and why that matters
IRMAA does not phase in gradually. Each bracket is a cliff: cross a threshold by a single dollar and you owe the full surcharge for that bracket — for the whole year, on both Part B and Part D. A couple sitting just above the first joint threshold can pay well over $2,000 a year more than a couple one dollar below it. The surcharge grows at every tier, reaching $487.00 a month for Part B at the top bracket in 2026.
Because the lookback is two years, the income decisions that set your IRMAA happen before you ever see the bill. A large IRA withdrawal, a Roth conversion, a home sale, or capital gains in 2024 can quietly push your 2026 premium into a higher bracket. The calculator above shows your current bracket and how many dollars of room you have before the next cliff — the single most useful number for planning withdrawals and conversions.
2026 Part B and Part D premiums
For 2026, the standard Part B premium is $202.90 per month and the national base Part D premium averages about $34.50 per month. IRMAA is added on top of these. Part B IRMAA ranges from $81.20 to $487.00 a month; Part D IRMAA ranges from $14.50 to $91.00 a month. Part B IRMAA is billed with your Part B premium (usually deducted from your Social Security check); Part D IRMAA is billed separately by Medicare even though your plan premium goes to a private insurer. See the full 2026 IRMAA bracket table for every tier.
What you can do about it
If your income recently dropped because of a life event — you retired, stopped or reduced work, lost a pension, divorced, or your spouse died — you do not have to wait two years. You can file Form SSA-44 and ask Social Security to use your current, lower income. If your high income was a one-time event, planning the timing of withdrawals and conversions in the years before Medicare is the most effective way to limit IRMAA.
Frequently asked questions
What income is used for 2026 IRMAA?
Your 2026 IRMAA is based on the MAGI from your 2024 federal tax return — your AGI (line 11) plus tax-exempt interest (line 2a). Social Security uses this two-year lookback because it is the most recent return the IRS can provide.
What is the IRMAA cliff?
Brackets are cliffs, not gradual phase-outs. One dollar over a threshold moves you into the next bracket and adds the full surcharge for both Part B and Part D for the entire year.
How much is the 2026 IRMAA surcharge?
The 2026 standard Part B premium is $202.90/month. IRMAA adds $81.20–$487.00/month for Part B and $14.50–$91.00/month for Part D, depending on your income tier.
Does tax-exempt interest count toward IRMAA?
Yes. Tax-exempt interest (such as from municipal bonds) is added back to your AGI when calculating MAGI for IRMAA, so it can push you over a threshold even though it isn't taxed.
Can I appeal my IRMAA?
Yes, with Form SSA-44 after a qualifying life-changing event such as retirement, marriage, divorce, death of a spouse, or loss of income-producing property. See our SSA-44 guide.