What Triggers IRMAA in 2026? The $103K and $206K Lines

Margaret is a 66-year-old widow filing single in Arizona. Her 2024 return showed $91,000 of adjusted gross income from a pension, a small RMD, and Social Security, plus $11,000 of tax-exempt municipal-bond interest she had always treated as “invisible” income. Add them together — $91,000 + $11,000 = $102,000 of IRMAA MAGI — and she sits just under the 2026 first cliff of $103,000. She pays the $185.00/month Part B base: $2,220.00 for the year.

Her neighbor Tom, also a single 66-year-old retiree, had nearly identical income but did one Roth conversion in 2024 that pushed his MAGI to $104,000 — about $1,000 over the line. Tom’s 2026 Part B premium jumps to $259/month, and a Part D surcharge of $13.70/month stacks on top. Tom pays approximately $1,052 more than Margaret for the year — on that last $1,000 of income. That is the IRMAA cliff, and this page tells you exactly where the lines are and what crossing each one costs.

The two lines that start IRMAA in 2026: $103K and $206K

IRMAA — the Income-Related Monthly Adjustment Amount — is a surcharge the Centers for Medicare & Medicaid Services (CMS) and the Social Security Administration (SSA) add to your Medicare Part B and Part D premiums when your income exceeds set thresholds. The legal authority is 42 U.S.C. §1395r(i), added by the Medicare Modernization Act of 2003 and expanded by the Affordable Care Act.

For 2026, the first surcharge tier begins above $103,000 of MAGI for single filers and $206,000 for married-filing-jointly. At or below those lines, you pay only the standard Part B base premium of $185.00/month and no Part D surcharge. The instant your MAGI crosses the line — by a dollar — you owe the first-tier adjustment on both Part B and Part D.

The full 2026 IRMAA tier table and what each line costs

Here are the 2026 brackets, the consequence at each line, and the annual extra cost per person. Premiums shown are projected 2026 figures; the Part B base is $185.00/month. Part D surcharges are the IRMAA add-on, charged on top of whatever your stand-alone drug plan or Medicare Advantage plan charges.

Read the “extra/yr per person” column carefully. For a married couple where both spouses are on Medicare, double it. A couple whose 2024 MAGI lands in the second MFJ tier ($258,001–$322,000) pays roughly $2,644 × 2 = $5,288 in IRMAA surcharges for the year, on top of their base premiums. The 2026 Part B base and surcharge dollar amounts shown are CMS projections to be confirmed in the final late-2025 announcement; the tier structure and the two-year lookback are statutory under 42 U.S.C. §1395r(i).

Why it’s a cliff, not a bracket: the marginal math

This is the single most misunderstood feature of IRMAA. Income-tax brackets are marginal: if you earn $1 over the 24% threshold, only that $1 is taxed at 24%. IRMAA is not marginal. It is a notch — the moment your MAGI crosses a line, your entire premium reprices upward.

Run the math on Tom’s $1,000 of excess income above. That $1,000 cost him about $1,052 in extra Medicare premiums — an effective marginal rate above 100% on the dollars that pushed him over. There is essentially no higher marginal “tax” rate anywhere in the U.S. system. This is why retirees who are within a few thousand dollars of a cliff should treat the threshold as a hard ceiling for Roth conversions, capital-gain harvesting, and discretionary IRA withdrawals.

1. Find your projected MAGI for the income year (two years before the premium year). For 2026 premiums, that is your 2024 return; for 2027 premiums, your 2025 return.
2. Add back tax-exempt interest. AGI from Form 1040 line 11 plus tax-exempt interest from line 2a equals IRMAA MAGI. Foreign-earned-income and savings-bond exclusions are also added back.
3. Identify the next cliff above your number. The gap between your MAGI and that line is your remaining “headroom” for conversions or gains.
4. Keep MAGI a buffer below the line — many planners leave $2,000–$5,000 of cushion to absorb a year-end 1099 surprise.

The two-year lookback: your 2026 premium is set by your 2024 return

IRMAA uses a two-year lookback written into 42 U.S.C. §1395r(i)(4). SSA determines your 2026 surcharge using the most recent IRS data on file — normally your 2024 tax return, filed in 2025. That lag is the planning window: the income that sets your 2026 premium is already locked, but the income that sets your 2027 and 2028 premiums is still in your control.

This is why IRMAA planning is forward-looking. A large Roth conversion or a one-time capital gain — the sale of a business, a rental property, or a concentrated stock position — lands on your premium two years later. Retirees who sell a home or convert a large traditional IRA without modeling the two-year-out IRMAA hit are routinely surprised by a CMS surcharge letter that arrives long after the transaction.

What the SSA letter looks like — and how to appeal

SSA mails an initial determination notice in the fall before the premium year. If your income has since dropped because of a qualifying life-changing event — work stoppage or reduction, marriage, divorce, death of a spouse, loss of pension, or loss of income-producing property — you can ask SSA to use a more recent year by filing Form SSA-44. The eight life-changing events are listed on the form. A retirement that cut your income in the premium year itself is the most common successful appeal.

What most people miss: muni-bond interest counts

The most expensive surprise in IRMAA is that tax-exempt municipal-bond interest is added back into MAGI. Retirees build muni-bond ladders precisely because the interest is exempt from federal income tax — but that same interest, reported on Form 1040 line 2a, is statutorily included in the IRMAA MAGI calculation under §1395r(i)(4).

For Margaret, the widow above, her $11,000 of muni interest was the entire difference between safely under the cliff and dangerously close to it. A retiree with $30,000 of muni interest who thinks of it as “tax-free and invisible” can be sitting two tiers higher than they realize. Three other items routinely overlooked:

• The taxable portion of Social Security. Up to 85% of your benefit is included in AGI (and therefore IRMAA MAGI) once combined income exceeds $34,000 single / $44,000 MFJ — thresholds that are not inflation-indexed.
• Required minimum distributions. Starting at age 73 (born 1951–1959) or 75 (born 1960+) under SECURE 2.0 §107, RMDs are fully taxable income that counts toward IRMAA — and they grow each year as the divisor shrinks.
• Capital gains, including the one-time ones. A home sale gain above the §121 exclusion ($250K single / $500K MFJ), a mutual-fund capital-gains distribution, or a portfolio rebalance all flow into MAGI two years before the premium hits.

The frozen fifth bracket: bracket creep until 2028

Most IRMAA thresholds are indexed to inflation and rise a few thousand dollars each year. The top tier is the exception. The highest threshold — $500,000 single / $750,000 MFJ — was fixed by statute and is not inflation-adjusted until 2028. Until then it stays flat while the lower tiers drift upward with inflation.

The practical effect is bracket creep by design: every year inflation lifts incomes, but the top line does not move, so more high earners are pulled into the top surcharge tier. If your MAGI is in the $450,000–$500,000 range and rising with portfolio growth, you should plan for the top bracket to capture you before the 2028 reset, not after.

Worked example: a couple deciding how much to convert

David (67) and Susan (66) file jointly in Florida — no state income tax. Their 2026 projected MAGI from pensions, RMDs, and taxable Social Security is $190,000, comfortably under the first MFJ cliff of $206,000. David wants to convert $40,000 of his traditional IRA to Roth in 2026 to shrink future RMDs.

The full $40,000 conversion costs David and Susan about $2,104 in IRMAA surcharges (both spouses, both on Medicare) on top of the income tax on the conversion. Capping the conversion at $15,000 — just under the $206,000 line — keeps them at the base premium. The decision is whether the long-term RMD reduction from the extra $25,000 of conversion is worth the $2,104 IRMAA toll. Often it is not in a single year, but it can be across a multi-year ladder — which is exactly the calculation the linked conversion-ceiling pages model.

How IRMAA fits the rest of your retirement-income plan

IRMAA is one tripwire in a sequence of them: the 0% vs. 15% capital-gains line ($48,350 single / $96,700 MFJ taxable income for 2026), the Net Investment Income Tax at $200K single / $250K MFJ (IRC §1411), the 22% vs. 24% income-tax bracket, and the Social Security taxation thresholds. A withdrawal that looks tax-efficient against one line can be expensive against another.

The diagnostic question this page answers — “am I going to get hit?” — is step one. If your projected MAGI for the relevant income year is within $10,000–$15,000 below a cliff, IRMAA should become a governing constraint on every discretionary income decision that year: how much to convert, when to realize gains, whether to take more than the required RMD.

The decision lever

IRMAA is not a tax you owe on income you already earned — it is a surcharge you can size in advance by controlling the MAGI on your 2024, 2025, and 2026 returns. Pull your most recent return, add line 11 to line 2a, and find the gap between that number and the next cliff above it. That gap is your annual conversion-and-gains budget. Stay a few thousand dollars under the line, and a single dollar of overage never costs you $1,052. Blow through it without modeling the two-year-out premium, and you pay the highest marginal rate in the code on income you never needed to recognize that year.

• The 2026 first cliff is $103,000 MAGI single / $206,000 MFJ, measured on your 2024 return under the two-year lookback (42 U.S.C. §1395r(i)).
• It is a one-dollar cliff: crossing the first single line costs ~$1,052/year; the top tier costs ~$6,356/year per person.
• MAGI for IRMAA = AGI (Form 1040 line 11) + tax-exempt interest (line 2a). Your muni-bond interest counts even though it is federally tax-free.
• The top tier ($500K single / $750K MFJ) is frozen until 2028, pulling more high earners into it via bracket creep.
• If a life-changing event dropped your income, appeal on Form SSA-44 to have SSA use a more recent year.
• Treat the next cliff above your projected MAGI as a hard ceiling for Roth conversions and capital-gain harvesting — the buffer below it is your decision budget.