2027 IRMAA brackets: the Medicare surcharge projection

The short answer. Your 2027 Medicare income-related monthly adjustment amount (IRMAA) is decided by the income on your 2025 tax return, because Medicare uses a two-year lookback. The official 2027 brackets are not yet published — the Centers for Medicare & Medicaid Services typically announces them around November 2026 — so any 2027 number here is a clearly labeled projection. What is confirmed is the 2026 structure, and that is enough to plan with: the first surcharge tier for 2026 begins at modified adjusted gross income (MAGI) over $109,000 single or $218,000 married filing jointly.

What IRMAA actually is

IRMAA is a surcharge bolted onto your Medicare Part B and Part D premiums once your income clears certain thresholds. The detail that catches people off guard is that it is a cliff, not a gentle ramp. A single dollar of income over a bracket threshold does not nudge your premium up slightly — it moves you into the next surcharge tier in full. Two retirees whose incomes differ by one dollar can pay meaningfully different Medicare premiums for an entire year, which is why the thresholds deserve real attention rather than a glance.

For 2026, the figures are settled. The standard Medicare Part B premium is $202.90 per month, paid by everyone on Part B. Above the first threshold, the confirmed 2026 Part B surcharges run from $81.20 to $487.00 per month depending on the tier, and the Part D surcharges run from $14.50 to $91.00 per month. Those figures come from the Centers for Medicare & Medicaid Services notice “Medicare Program; Medicare Part B Monthly Actuarial Rates, Premium Rates, and Annual Deductible Beginning January 1, 2026”, published in the Federal Register on November 19, 2025. Those surcharges are stacked on top of your underlying premiums, so a high earner in the top tier is paying the standard premium plus the surcharge, every month, for the year.

That standard premium is also the figure that interacts directly with your Social Security check, since most beneficiaries have Part B deducted straight from their monthly deposit. How that $202.90 premium plays against the annual cost-of-living adjustment — including the provision that can cap the deduction so a premium increase does not shrink your net check — is covered in our Social Security COLA tracker.

The two-year lookback is the whole game

Here is the mechanism that makes this page worth reading in mid-2026 rather than in late 2027: your IRMAA is based on your MAGI from two years earlier. Your 2026 surcharge is built from your 2024 return. And your 2027 surcharge will be built from your 2025 MAGI — the income on the return you file in 2026. The decision is already in motion.

That lag is the reason a Medicare premium can feel like it arrived out of nowhere. A beneficiary remembers a single strong income year — a property sale, a large capital gain, a one-time distribution — and only feels the surcharge two years later, long after the cause has faded from memory. The flip side is the good news. Because 2027 keys off 2025, you still have room in 2025 to manage the income that sets it.

What counts toward MAGI for IRMAA

The income measure that triggers a surcharge is a specific one. For IRMAA, MAGI is your adjusted gross income (AGI) plus tax-exempt interest, such as the interest from municipal bonds. Municipal bond interest is famously free of federal income tax, but it is not invisible to Medicare — it climbs back in for this calculation. (For the broader definition, see our explainer on MAGI.)

The components are wide-ranging. MAGI for IRMAA counts wages, interest, dividends, capital gains, distributions from traditional retirement accounts, rental income, and the taxable portion of your Social Security benefits. Because AGI sits at the heart of it, it helps to understand how that figure is built up from a W-2 and your other income before tax-exempt interest is added back. The takeaway is that a single large realization event — selling an appreciated stock, taking a big traditional-IRA withdrawal, converting to a Roth — flows straight into the number that decides your premium.

How the 2027 brackets are projected

The 2027 figures are not yet known, and it matters that we say so plainly. The official 2027 IRMAA brackets and premiums are set by the Centers for Medicare & Medicaid Services and are typically announced around November 2026. Until then, every 2027 number is a projection, and we will update this page when the agency publishes the real ones.

We can still describe the direction of travel, because the mechanism is defined. The IRMAA thresholds are adjusted annually for inflation using the Consumer Price Index (CPI-U), so they drift upward modestly each year. The 2026 thresholds themselves rose from 2025 — the first single tier moved from $106,000 to $109,000, and the married threshold from $212,000 to $218,000 — which shows the indexing in action.

Unlike the FSA cap, the 401(k) limit, and the tax brackets tracked elsewhere on this site, IRMAA is not indexed off the chained C-CPI-U. Under 42 U.S.C. §1395r(i)(5), the thresholds move with the plain CPI-U — the Bureau of Labor Statistics’ broader urban index — averaged over the 12 months ending August 31 and compared against a fixed base of 249.280, the average CPI-U for the 12 months ending August 2018. Each result rounds to the nearest $1,000. (The additional $500,000 and $750,000 top brackets added in recent years stay frozen; they are not scheduled to index until 2028.)

The method checks out first: running the same 12-month-to-August formula against last year’s data reproduces the confirmed 2026 single thresholds — $109,000, $137,000, $171,000 and $205,000 — exactly, the same discipline this site applies to every other 2027 projection before trusting the formula with next year’s numbers.

The CPI-U window is now closed: the Bureau of Labor Statistics published August 2026 on September 11, completing eleven of the twelve months the statute uses — September 2025 through August 2026, since October 2025 was never collected because of that year’s government shutdown. Those eleven months average 329.6563, a ratio of 1.32244 against the fixed 2018 base of 249.2802. Applying that ratio to the four thresholds set in 2018, the four 2027 single thresholds project to:

Tier	2026 official (single)	2027 central (single)	2027 if October is imputed (single)
1st	$109,000	$112,000	$112,000
2nd	$137,000	$142,000	$141,000
3rd	$171,000	$177,000	$176,000
4th	$205,000	$212,000	$211,000

Married-filing-jointly thresholds run exactly double the single figures: $224,000 / $284,000 / $354,000 / $424,000 in the central scenario, versus $224,000 / $282,000 / $352,000 / $422,000 if the calculation imputes the missing October 2025 month.

Some of those thresholds are firmer than others. The first tier, $112,000, is effectively decided in either scenario — its unrounded central value is $112,407, nowhere near a rounding edge. The fourth tier is likewise settled at $212,000 in the central case, with an unrounded value of $211,589, comfortably clear of the $211,500 line that would round it down. The tier actually worth watching is the second: its unrounded central value is $141,500.31, just above the $141,500 line that separates $141,000 from $142,000 — an August CPI-U reading of 334.97 instead of the 334.980 that actually published would have rounded the whole tier down a step. That is the closest call on this page, and the one to watch when the Centers for Medicare & Medicaid Services confirms the real figure around November. The third tier’s unrounded value, $176,545, sits with more room above its own $176,500 rounding line.

What still moves the fourth-tier figure — and only the fourth tier — is no longer the size of the August print, which is now fixed, but whether the eventual IRS-and-CMS calculation imputes an estimated October 2025 reading or averages the eleven months that actually exist. Averaging the eleven real months gives the $212,000 central figure above; imputing October instead pulls the 12-month average down slightly and rounds the top tier to $211,000 single / $422,000 married.

The August CPI-U reading published on September 11, 2026, as scheduled, the same day as the C-CPI-U release behind the IRS 2027 inflation adjustments tracker, which walks through the brackets, the FSA cap, and the gift exclusion decided by that same week of data through a related but different formula. Do not file a return or skip a conversion on the strength of a projected bracket even so — use these numbers to understand where the lines are likely to sit, not as a substitute for the CMS announcement in November.

Why this is a 2025 planning problem

The practical reason to read a 2027 projection in 2026 is that the levers are pulled now. Because 2027 IRMAA keys off 2025 MAGI, any action that raises your 2025 income can tip you over a 2027 cliff: a large Roth conversion, realizing a substantial capital gain, or taking a lump-sum distribution in 2025 all land in the figure that sets the surcharge. Conversely, spreading income across years, timing a conversion to fill a bracket rather than overflow it, or deferring a sale into a lower-income year keeps you under the line.

The cliff structure raises the stakes on these decisions. Because crossing a threshold by a dollar triggers the full surcharge for the next tier, the cost of a slightly-too-large conversion is not a few dollars — it can be a full step up in your Part B and Part D premiums for all of 2027. That asymmetry is exactly why the modeling belongs in your 2025 tax planning, before the year closes, rather than in your 2027 budget after the bill arrives. Keep an eye out for the official Centers for Medicare & Medicaid Services figures around November 2026; this page will be updated to reflect them.