What Is IRMAA?

The surcharge in plain English

Most people pay the standard Medicare Part B premium — $202.90 per month in 2026. IRMAA is not a separate bill or a different program. It is an extra amount the Social Security Administration adds to your premium when your income is high enough. Think of it as a high-income surcharge layered on top of the premiums everyone else pays.

Who pays IRMAA

You pay IRMAA only if your Modified Adjusted Gross Income (MAGI) is above the first threshold for your filing status. In 2026 that line is $109,000 for a single filer and $218,000 for a married couple filing jointly. The vast majority of beneficiaries fall below those levels and pay only the standard premium. If you are above them, you owe a surcharge that grows as your income climbs. You can see the full schedule on our 2026 IRMAA brackets page.

It applies to Part B and Part D

IRMAA hits two parts of Medicare. The Part B surcharge is added to your medical-insurance premium. The Part D surcharge is added to your prescription drug coverage — and it is owed even if your drug plan comes from a private insurer, because Medicare collects the IRMAA portion directly. So a high-income beneficiary can pay two separate surcharges every month.

The two-year lookback

Medicare does not use your current income to set IRMAA. It uses a two-year lookback: your 2026 surcharge is based on the MAGI reported on your 2024 tax return, the most recent return the IRS has shared with Social Security. MAGI is your adjusted gross income plus any tax-exempt interest, so municipal bond interest still counts. Because of this lag, a one-time income spike — selling a home, a large Roth conversion, or a big retirement withdrawal — can raise your premiums two years later, even after your income returns to normal.

How it is deducted

If you collect Social Security, the Part B surcharge is taken straight out of your monthly benefit before it reaches you. If you are not yet drawing Social Security, Medicare sends you a quarterly bill. The Part D surcharge is always paid to Medicare rather than to your drug plan.

IRMAA is a cliff, not a slope

This is the detail that surprises people most. IRMAA is tiered, and each tier is a cliff. Cross a threshold by a single dollar and you pay the full surcharge for that entire tier — there is no gradual phase-in. That is why managing income near a threshold matters so much. Run your own numbers with our IRMAA calculator, then read our planning strategies if you are close to a bracket.

It is recalculated every year

Because IRMAA is reset annually using fresh tax data, it is not a permanent label. As your income changes, your surcharge can rise, fall, or vanish entirely. And if your income dropped because of a qualifying event, you do not have to wait two years — you can appeal using Form SSA-44 to have Social Security use your current income instead.