What Are the 2026 IRMAA Brackets?

Unlike income tax brackets, where only the income above a threshold is taxed at the higher rate, IRMAA is a cliff. Cross a threshold by even one dollar and your entire Part B and Part D premium jumps to the new tier's full amount, not just the marginal dollar. That makes precise MAGI management far more valuable near a threshold than most retirees expect.

The standard 2026 Part B premium is $202.90 per month, with a $283 annual deductible. The five IRMAA tiers, based on 2024 MAGI, are: $109,001–$137,000 single ($218,001–$274,000 married) pays a total Part B premium of $284.10 plus $14.50 for Part D; $137,001–$171,000 single ($274,001–$342,000 married) pays $405.80 for Part B plus $37.50 for Part D; $171,001–$205,000 single ($342,001–$410,000 married) pays $527.40 for Part B plus $60.40 for Part D; $205,001–$500,000 single ($410,001–$750,000 married) pays $649.20 for Part B plus $83.30 for Part D; and above $500,000 single ($750,000 married) pays the top rate of $689.90 for Part B plus $91.00 for Part D.

Married filing separately gets a much less forgiving version of this table. Instead of five graduated tiers, MFS filers go from the standard premium directly to a tier equivalent to the second-highest bracket (around $649.20 Part B plus $83.30 Part D) once MAGI exceeds $109,000, then to the top tier above roughly $394,000. There's no gentle on-ramp the way single and joint filers get, which is a genuine consideration for couples weighing whether to file separately for other tax reasons.

Every bracket dollar figure is indexed to inflation except the top tier, which was set in statute by the Bipartisan Budget Act of 2018 at $500,000 single/$750,000 married and stays fixed until ordinary tax brackets catch up to it through inflation, a point that's still years away. The lower four thresholds move each year based on the CPI-U measured over the 12 months ending in August, which is why the 2026 thresholds only moved up modestly (about 2.8%) from 2025's $106,000/$212,000 starting point, even though the standard Part B premium itself jumped nearly 10%.

For 2027, CMS won't publish final numbers until around November 2026, after a full year of CPI data is available. Early projections based on partial data point to a 2027 starting threshold somewhere in the $112,000-$113,000 range for single filers, roughly double for joint filers, but treat any 2027 figure you see before the official CMS announcement as an estimate, not a number to plan precisely around.

Because this is a cliff rather than a slope, the right planning move near a threshold isn't to land exactly at the limit, it's to build in a buffer. A capital gain distribution in December, an unexpectedly large dividend, or a slightly underestimated Roth conversion can push you a few hundred dollars over a threshold and cost you the entire next tier's surcharge, often $1,000 or more per year per person.

Since IRMAA uses your MAGI from two years earlier, the return you file for the current tax year is the one to model against these tables, not your income right now. If you'll be on Medicare in two years, treat this year's income decisions as Medicare premium decisions, not just tax decisions.

• Treating IRMAA like a marginal tax bracket, where only the income above the line gets the higher rate. Crossing the line reprices your entire premium.
• Not accounting for year-end mutual fund capital gain distributions, which can push MAGI over a threshold without any deliberate withdrawal or conversion decision.
• Assuming the top bracket adjusts for inflation every year like the other four; it's fixed by statute and has stayed at $500,000/$750,000 since 2018.
• Planning a Roth conversion or asset sale for the current year without checking what it does to the IRMAA bracket two years from now.