IRMAA Calculator 2026: Will This Year’s Income Raise Your 2028 Premiums?

What IRMAA Is and Why It Matters

IRMAA — the Income-Related Monthly Adjustment Amount — is a Medicare surcharge on enrollees whose modified adjusted gross income two years earlier was above $109,000 (single) or $218,000 (married filing jointly) for 2026. Cross the income threshold by even one dollar and you pay the full surcharge for that tier. There is no gradual phase-in.

The 2026 IRMAA brackets for Medicare Part B:

For a couple in the first surcharge tier, counting Part B and Part D together as the calculator above does, that is $2,297 per year in extra premiums. At the top tier: $13,872 per year — money that comes directly out of your retirement income.

The Two-Year Lookback Problem

IRMAA is determined by your Modified Adjusted Gross Income from two years prior. Your 2026 Medicare premiums are based on your 2024 tax return. This means the Roth conversion you did in 2024 — or the capital gain you took, or the RMD you received — is setting your Medicare costs right now.

Most retirees discover IRMAA after the fact. Planning requires looking forward: what will my MAGI be in each year, and how does that cascade into Medicare premiums two years later?

What IRMAA Modeling Has to Get Right

Check whether the tool you use models IRMAA at all, and whether it applies a single inflation rate to both MAGI thresholds and premium amounts. A single rate produces misleading results.

The reality is that IRMAA has two inflation components:

1. MAGI thresholds adjust by CPI (~2.5% historically)
2. Premium surcharges inflate at the medical inflation rate (~5% historically)

Over a 30-year retirement, this divergence is massive. A Tier 1 Part B surcharge that costs a couple $1,949/year today costs about $5,171/year in year 20 at 5% medical inflation — but only about $3,194/year if you assume 2.5% CPI for both. Summed over 30 years that is roughly a $43,900 understatement for one couple who stays in the same tier.

QuantCalc decouples these rates. The medicareInflationRate parameter applies medical-specific inflation to premium amounts while CPI governs threshold adjustments.

Strategic IRMAA Avoidance

The primary lever is Roth conversion timing. Convert too much in one year and you spike your MAGI into a higher IRMAA tier two years later. Convert too little and you face larger RMDs that push you into IRMAA permanently once they start (at 73, or 75 if you were born in 1960 or later).

QuantCalc's Roth conversion optimizer offers two modes:

• Fixed dollar conversion: Convert a set amount per year (e.g., $50,000/year from age 60-72)
• Bracket-fill-to-ceiling: Each year converts up to the taxable-income ceiling you set — the top of a bracket, or a lower figure you choose to stay under an IRMAA threshold. It estimates taxable Social Security as 85% of the benefit when sizing the conversion; it does not cap the conversion at an IRMAA threshold on its own.

Both modes run across 10,000 Monte Carlo scenarios with stochastic market returns, so you see the probability of IRMAA exposure across thousands of possible futures.

IRMAA and ACA: The Dual Cliff

Early retirees face a unique challenge: before 65, keeping MAGI below the ACA subsidy cliff (400% FPL) saves $15,000+/year in health insurance. After 65, keeping MAGI below IRMAA thresholds saves $1,900-$11,700/year in Medicare premiums. QuantCalc covers both: the ACA Bridge Planner sizes conversions year by year against the ACA cliff and the IRMAA lookback until Medicare, and the retirement planner prices IRMAA for every year after that.

Will my 2026 income raise my 2028 Medicare premiums?

It does if your 2026 MAGI ends above an IRMAA floor, because Medicare reads the tax return from two years before. A single 72-year-old whose 2026 MAGI is $109,200 is over the first floor and pays about $1,148.40 of surcharges in 2028 at the 2026 tiers; a $10,000 QCD instead of IRA income removes it.

What is IRMAA?

IRMAA (Income-Related Monthly Adjustment Amount) is a Medicare surcharge added to your Part B and Part D premiums when your Modified Adjusted Gross Income exceeds $109,000 (single) or $218,000 (joint). It is determined by your tax return from two years prior.

How is IRMAA calculated?

IRMAA uses your Modified Adjusted Gross Income (MAGI) from two years prior. For 2026 premiums, your 2024 MAGI determines your tier. Surcharges range from $81.20 to $487.00 per month per person for Part B, with additional Part D surcharges.

Do Roth conversions help with IRMAA later?

They can, and they cost IRMAA room now. A conversion adds to MAGI in the year you convert, so it can raise the premiums two years later; it also shrinks the traditional balance that later Required Minimum Distributions (from 73, or 75 if born in 1960 or later) are figured on. The calculator above shows how much more income fits before your next floor this year.

What are the 2026 IRMAA brackets?

2026 IRMAA brackets for single filers: up to $109,000 (no surcharge), $109,001-$137,000 (+$81.20/mo), $137,001-$171,000 (+$202.90/mo), $171,001-$205,000 (+$324.60/mo), $205,001-$499,999 (+$446.30/mo), $500,000 and above (+$487.00/mo). Joint filers have approximately double thresholds.