RetirementEquation
IRMAA thresholds

What changes IRMAA MAGI, and what each threshold costs

IRMAA is set from modified adjusted gross income in a single tax year. This page sets out what enters that figure, what does not, and what each threshold costs to cross.

What each threshold costs to cross

These are 2026 figures, Part B and Part D surcharges combined, for a full year. One dollar of income decides each of them.

Crossing (single)Or jointlyPer monthPer yearCouple, both on Medicare
$109,000$218,000$95.70$1,148.40$2,296.80
$137,000$274,000$144.70$1,736.40$3,472.80
$171,000$342,000$144.60$1,735.20$3,470.40
$205,000$410,000$144.60$1,735.20$3,470.40
$500,000$750,000$48.40$580.80$1,161.60

Computed from the published 2026 surcharges — see the full table and where the figures come from. Each spouse pays separately, so a couple crossing together pays twice.

One dollar over a threshold

Being $1 over the $137,000 line costs $1,736.40 for the year, or $3,472.80 for a couple. A step that reduces tax by less than that, while raising MAGI past the threshold, costs more than it saves.

IRMAA uses MAGI, and only MAGI

Anything that changes the surcharge does so by changing modified adjusted gross income in a specific year. MAGI here is adjusted gross income plus tax-exempt interest. Deductions below the AGI line, marginal tax rate and net worth do not enter the calculation.

The figure that matters is the distance between current MAGI and the next threshold, and what would fill it.

What changes MAGI

Four mechanisms that enter the MAGI calculation, and how each one is treated. They are numbered for reference, not ranked, and nothing here is a recommendation — whether any of them fits a particular situation depends on facts this page cannot see.

1
Qualified charitable distributions
A QCD goes straight from an IRA to the charity and is excluded from income — so it lowers AGI, and therefore MAGI, dollar for dollar. It also counts toward a required minimum distribution. There is an annual cap, indexed yearly; the current figure is published by the IRS.
2
The size of a Roth conversion
A conversion is ordinary income in the year it is made, so it adds to MAGI dollar for dollar. A conversion that fits inside the remaining headroom leaves the bracket unchanged; one that runs past the threshold moves the whole year up a tier. Crossing the $109,000 line by any amount costs $1,148.40 in surcharges for the year, on top of the tax on the conversion itself.
3
The timing of capital gains
Realised gains land in the year of the sale, so a single large disposal can clear several tiers at once. The same gain split across two tax years, or reported under instalment treatment where that is available, is counted in each year separately. Realised losses offset gains and so reduce AGI directly.
4
Which account a withdrawal comes from
Qualified Roth withdrawals are not income and do not appear in MAGI at all, while traditional IRA and 401(k) withdrawals are ordinary income and count in full. Two withdrawals of the same size therefore have different effects on the bracket depending only on which account they come from.

What does not change MAGI

Commonly suggestedHow it is treated
Municipal bondsTax-exempt interest is added back for MAGI. Form SSA-44 asks for it explicitly, from line 2a of your 1040. Free of income tax, still counts here.
Itemised charitable deductionsThey reduce taxable income, not AGI — so they do not move your IRMAA bracket. Only a QCD, which is excluded from income in the first place, does.
Most other deductions below the lineSame reason. IRMAA is set from AGI plus tax-exempt interest, which sits above most of what people think of as deductions.
HSA contributionsThey do reduce AGI — but you cannot contribute to an HSA once you are enrolled in Medicare, so this is not available to the people IRMAA applies to.
Appealing a high-income yearA large income year is not a life-changing event, however much it raised your MAGI. SSA-44 is for circumstances that changed your income going forward — retirement, bereavement, divorce — not for one-off gains.
Waiting it outThe year that set your current surcharge is already filed and unchangeable. Waiting works only in the sense that a one-off year affects twelve months of premiums and no more.

Which year a decision lands in

Because IRMAA uses a two-year lookback, the year still open is not the year being charged for. The 2026 surcharge comes from the 2024 return, which is already filed.

Income in the current year sets the surcharge two years out. Conversions, sales and withdrawals made now fall in the 2028 bracket, not the current one.

The calendar consequence: once a year closes, that year’s MAGI is fixed, and with it a premium two years later. December is the last month in which any of it is still open.

If MAGI is already above a threshold

If your income fell because of a life-changing event — retirement, reduced hours, a spouse’s death, divorce, a lost pension — you can ask Social Security to use a more recent year rather than waiting for the two-year lookback to move past it. That is what Form SSA-44 is for. There is no fee to file it.

A single high-income year with no life-changing event does not qualify for SSA-44. The surcharge applies for twelve months, after which SSA uses the next return.

What this page is and is not

This page explains mechanisms and does the IRMAA arithmetic. It is not tax, legal or financial advice, it is not a recommendation to take or avoid any of the actions described, and it takes no account of anyone’s individual circumstances. The limits attached to QCDs, capital losses and retirement accounts change from year to year; the current figures are published by the IRS, and a tax professional can apply them to a particular situation. What this page can state precisely is what a threshold costs, because that comes straight from CMS. If a figure here is wrong, tell us and we will correct it.