IRMAA Surcharges Explained

Why did your Medicare premium suddenly jump when nothing about your health changed? Because of IRMAA, the income-related surcharge that bolts onto your Medicare bill when your income climbs. It’s a stealth tax on looking wealthy on paper, and high-net-worth retirees walk into it constantly.

What it actually is

IRMAA stands for the income-related monthly adjustment amount. In plain terms, the more income you report, the more you pay on top of the standard Medicare Part B and Part D premiums. For 2026, the standard Part B premium is $202.90 a month. Cross into the surcharge tiers and that number climbs fast, all the way to a total Part B premium of $689.90 a month at the top bracket.

That’s the same Medicare coverage. You’re just paying a premium for your income.

The cruelest part: the cliff and the time machine

Two features make IRMAA bite harder than a normal tax, and both catch people off guard.

First, it’s a cliff, not a ramp. Regular taxes phase in gradually. IRMAA jumps in steps. Go one dollar over a bracket line and the full surcharge for that tier hits, so a single dollar of extra income can cost you hundreds of dollars over the year. The bracket-by-bracket map is in Medicare IRMAA brackets explained.

Second, it runs on a two-year delay. Your 2026 premium is set by the income on your 2024 tax return. So a one-time spike from years ago reaches forward and taxes you today. Sell a property, do a big Roth conversion, or take a fat capital gain, and the Medicare bill shows up two years later when you’ve forgotten all about it.

Where retirees trip the wire

The usual suspects are predictable once you know to watch for them. A large Roth conversion. A home sale with decades of gains. The first wave of required minimum distributions at 73 or 75, which can push income up exactly when you stop controlling it. Even a strong year of dividends and capital gains can nudge you over a line.

The fix is the same one good tax planning always uses: watch the brackets and manage income to them. If a conversion would clear a tier by a hair, you stop just under the line and finish next year. If a life event already blew past a bracket, sometimes you lean into that year because you’ve taken the hit anyway. And if a one-time event like retirement or a property sale caused the spike, you can appeal IRMAA directly using Form SSA-44.

The takeaway

IRMAA punishes the surprised and rewards the planner. It’s a cliff, it reads a tax return from two years back, and it’s almost entirely avoidable if you see it coming. Watch the lines before you cross them, because the surcharge is already watching you.