The $106,000 Line Most Retirees Cross by Accident – and the $2,000 Medicare Surcharge It Triggers.

The first required minimum distribution generally starts for the year you turn 73. Add a capital gain from selling a rental, a year-end Roth conversion, or a few thousand dollars of municipal bond interest, and a retiree who has never paid a Medicare income surcharge can cross the first IRMAA line without realizing it. Two years later, the bill shows up in the Part B premium.

This is the Income-Related Monthly Adjustment Amount, or IRMAA, and it touches a narrow slice of Medicare. CMS says income-related Part B adjustments affect about 8% of people with Medicare Part B. A reader sitting comfortably below the first threshold may not need to worry this year. A reader within $20,000 of the line, or planning anything that creates a one-time income spike, needs the math below.

The 2026 line and what crossing it costs

For Medicare premiums in 2026, the first IRMAA threshold begins above $109,000 in modified adjusted gross income for single filers and above $218,000 for joint filers. The line moved up from $106,000 single in 2025 because of inflation indexing. Cross the line by a dollar and Medicare adds $81.20 per person per month to Part B and $14.50 per person per month to Part D. That is $95.70 a month per person, $1,148.40 a year per person, and $2,296.80 a year for a couple where both spouses are on Medicare.

Two features make IRMAA bite harder than the headline suggests. It works as a cliff: one dollar over the threshold triggers the entire tier. And the surcharge climbs steeply. At the top tier, which begins at MAGI of $500,000 or more for single filers and $750,000 or more for joint filers, the combined Part B and Part D surcharge reaches $578 per person per month.

MAGI counts things people forget

For IRMAA, MAGI is adjusted gross income from Form 1040, line 11, plus tax-exempt interest from line 2a. The tax-exempt interest add-back catches retirees who shifted income into municipal bonds for “tax-free” cash flow. The IRS may exempt that interest from federal income tax, but Social Security still counts it when determining Medicare IRMAA.

The lookback generally runs two years. The 2026 Part B premium generally reflects the 2024 tax return. The 2027 premium will generally reflect 2025. The 2028 premium generally reflects 2026. Anything that lifted 2024 MAGI above the line may already be built into this year’s bill unless a qualifying SSA-44 event applies. The window a retiree can still steer is calendar 2026, which generally sets the 2028 premium.

The accidental triggers

A 67-year-old living on Social Security and modest withdrawals rarely brushes the line. The crossings often come from taxable events that are large, badly timed, or easy to overlook:

• The first RMD. Required minimum distributions generally begin at age 73, or 75 for those born in 1960 or later. A $1.5 million traditional IRA at 73 can force out roughly $57,000 in mandatory taxable income whether the retiree needs the cash or not.
• A Roth conversion. The taxable amount converted lands in MAGI in the conversion year. A $50,000 conversion stacked on Social Security and a pension is enough to push many couples past $218,000.
• A capital gain. Selling a rental, downsizing the primary home with gain above the $500,000 joint exclusion, or rebalancing a taxable brokerage can flow through AGI.
  Severance, deferred comp, or a pension lump sum. These often land the same year someone enrolls in Medicare.

The survivor trap

When a spouse dies, the survivor may still be able to file jointly for the year of death, but many older survivors eventually file as single. Single IRMAA brackets sit at roughly half the joint amounts. A widow whose household income comfortably sat under $218,000 joint can land in a higher IRMAA tier on her own if income does not fall enough. Nothing about her spending may have changed. The bracket did.

What SSA-44 can and cannot fix

Form SSA-44 lets a beneficiary request a lower IRMAA amount when income dropped because of a qualifying life-changing event: marriage, divorce or annulment, death of a spouse, work stoppage, work reduction, loss of income-producing property, loss of pension income, or certain employer settlement payments. It does not reverse voluntary income events. A Roth conversion or voluntary property sale generally will not qualify just because it spiked MAGI.

What to do this year

• Model the line before December. Add projected AGI and tax-exempt interest. If you are within $20,000 of $109,000 single or $218,000 joint, consider deferring discretionary income to a year with more headroom or splitting a controllable event across two tax years.
• Use QCDs once you qualify. Qualified Charitable Distributions from an IRA, available beginning at age 70½, can count toward the RMD but are excluded from AGI when made properly. For a retiree who already gives, this can be one of the cleanest ways to keep IRA dollars out of the IRMAA calculation.
• File SSA-44 promptly after a qualifying life-changing event reduces income. Retirement, work reduction, or the death of a spouse can support a request when documentation such as an employer statement, proof of work reduction, or death certificate shows the event and the lower income year. Do not wait for the two-year lookback to catch up on its own.

The Line Is Easier to Avoid Before You Cross It

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