Medicare IRMAA Calculator
Find your 2026 Medicare Part B and D premiums from your 2024 income, see which IRMAA bracket you land in, and how close you are to the next cliff.
How to use this calculator
- 1Enter your modified adjusted gross income from your 2024 tax return — AGI plus any tax-exempt interest.
- 2Choose your filing status for that year, not this one.
- 3Tick both spouses if you are both enrolled in Medicare, since the surcharge is charged per person.
- 4Check the room before the next cliff — that figure is what any year-end income decision has to stay inside.
How the calculation works
Premium = Part B for your bracket + Part D surcharge, per enrolled person. Bracket is set by MAGI from two years earlier- MAGI
- Adjusted gross income plus tax-exempt interest — Form 1040 line 11 plus line 2a
- two years earlier
- 2026 premiums are determined by the 2024 return filed in 2025
IRMAA is a cliff. Every bracket applies in full the moment income exceeds the threshold by any amount, so one extra dollar of income can cost hundreds or thousands of dollars over the following year.
The surcharge is per person. A married couple who are both enrolled pay it twice, which doubles the cost of crossing a threshold.
Married filing separately while living together removes all intermediate tiers — income above the first threshold jumps almost directly to the highest surcharge.
Worked example
$150,000 of 2024 income, single
- 1.$150,000 falls in the third tier for a single filer, which runs from $137,001 to $171,000.
- 2.Part B is $405.80 a month rather than the standard $202.90, and Part D adds $37.50.
- 3.That is $443.30 a month, or $5,319.60 a year — about $2,884 more than the standard premium.
Result: Roughly $2,900 a year of surcharge
Just below a threshold
- 1.$136,500 sits $500 below the $137,000 threshold, so the second-tier rates apply.
- 2.Part B is $284.10 plus $14.50 of Part D — $298.60 a month.
- 3.Earning $501 more would move you into the next tier at $443.30 a month, costing about $1,736 more for the year.
- 4.That is an effective marginal rate of several hundred per cent on those few hundred dollars.
Result: A $500 cushion worth about $1,736
What IRMAA is and why it surprises people
Medicare Part B and Part D are subsidised, but the subsidy shrinks as income rises. The income-related monthly adjustment amount is the surcharge that removes it — higher earners pay a larger share of the true cost, up to roughly 85% of it at the top bracket.
Two features make it far more painful than a normal means test. The first is the two-year lookback: 2026 premiums are set by income reported on the 2024 return. Someone who sold a property, converted a large sum to a Roth, or received a final bonus before retiring in 2024 discovers the consequence in 2026, when their income may be a fraction of what triggered it.
The second is that it is a cliff rather than a taper. Cross a threshold by one dollar and the entire surcharge for that bracket applies for twelve months. Ordinary tax brackets only tax the excess; IRMAA charges the full step. That produces effective marginal rates in the hundreds or thousands of per cent on the last few dollars before a threshold, and it is why year-end income management matters so much for anyone near a line.
Managing income around the thresholds
Because the cliffs are known in advance, they can be planned around — and the two-year lag actually helps, since the income that matters is being earned now for a premium two years out.
- Watch the year, not the moment — the threshold applies to the full calendar year's MAGI. A December decision — realising a gain, taking an extra distribution, converting to a Roth — is the last chance to stay under a line, and the easiest to get wrong.
- Size Roth conversions to the threshold — conversions are one of the largest controllable inputs to MAGI. Converting exactly up to a threshold captures the tax benefit without triggering the surcharge; a dollar more triggers the whole step.
- Use qualified charitable distributions — sending an IRA required distribution directly to charity excludes it from AGI entirely, which is more effective for IRMAA than taking the distribution and claiming a deduction.
- Remember tax-exempt interest counts — municipal bond interest is free of income tax but is explicitly added back for the IRMAA calculation, so it can push someone over a threshold that their taxable income alone would not.
- Appeal after a life-changing event — form SSA-44 lets you have the surcharge recalculated on current income after retirement, divorce, widowhood, or loss of a pension or business. This is the single most under-used remedy — many newly retired people pay a surcharge based on their final working year without realising it can be appealed.
What this assumes, and where it stops
Assumptions
- Premiums are the announced 2026 figures, applied to modified AGI from the 2024 tax year.
- Part D surcharge is the IRMAA amount only — your plan's own premium is charged on top and varies by plan.
- The married-filing-separately schedule assumes the spouses lived together at some point during the year.
- No life-changing-event appeal has been granted.
Limitations
- The Part D figure is the surcharge alone. Your total drug plan cost depends on the plan you choose.
- Medicare Advantage and Medigap premiums are separate and not included.
- Premium amounts are as published for 2026; confirm your own figure against the notice from Social Security, which is authoritative for your account.
- A successful SSA-44 appeal after a life-changing event can reduce or remove the surcharge entirely, which this cannot model.
Common questions
Why am I paying IRMAA when my income is now much lower?
Because Medicare uses your tax return from two years earlier. Your 2026 premium comes from your 2024 income, so a final year of salary, a property sale or a Roth conversion in 2024 sets what you pay now. If the drop was caused by a life-changing event — retirement, divorce, death of a spouse, loss of a pension — you can file form SSA-44 to have it recalculated on current income, which is frequently worth doing.
What counts toward MAGI for IRMAA?
Adjusted gross income from Form 1040 line 11, plus tax-exempt interest from line 2a. That means municipal bond interest counts even though it is free of income tax. Roth conversions, capital gains, required minimum distributions, pension income and the taxable part of Social Security all feed into it. Roth withdrawals and qualified charitable distributions do not.
How much does going one dollar over a threshold cost?
The entire step for that bracket, for twelve months. Depending on which threshold you cross, that is roughly $1,400 to $2,500 a year per person — and double for a couple who are both enrolled. There is no proration or taper, which is what makes the last few hundred dollars of income before a threshold some of the most expensive money in the tax system.
Can I appeal an IRMAA determination?
Yes, using form SSA-44, if a specific life-changing event caused your income to fall — retirement or reduced work hours, marriage, divorce, death of a spouse, loss of a pension, or loss of income-producing property. You supply evidence of the event and your expected current income, and the surcharge is recomputed. Simply having lower income without a qualifying event does not support an appeal.
Sources
- Medicare Costs: Part B Premiums — US Centers for Medicare & Medicaid Services
- Medicare Premiums: Rules for Higher-Income Beneficiaries — US Social Security Administration
- Form SSA-44: Medicare Income-Related Monthly Adjustment Amount — Life-Changing Event — US Social Security Administration
Formula and content last reviewed on .
Results are estimates for information only, not professional advice.
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