2026 IRMAA Calculator: Medicare Part B & D Surcharge

Use this IRMAA calculator two ways: get a quick estimate of your published 2026 Medicare Part B and Part D IRMAA using 2024 MAGI, or switch to Planning / What-If mode to test how a Roth conversion, taxable capital gain, QCD offset, or another income change could move you across an IRMAA threshold.

The big catch is timing. Your 2026 IRMAA is generally based on income from 2024. So the financial move that creates the surcharge and the Medicare bill that reminds you about it can be separated by two years. That delay is what makes IRMAA planning feel sneakier than it really is.

How to Use the IRMAA Calculator

If all you want is your 2026 estimate, keep the calculator on Quick Estimate. You need two things: the filing status from the tax return Medicare is using and your 2024 IRMAA MAGI.

1. Select your 2024 filing status. Single/head of household, married filing jointly, or the special married-filing-separately table.
2. Enter your 2024 MAGI. For IRMAA, this is generally adjusted gross income plus tax-exempt interest.
3. Calculate. The result shows your estimated 2026 Part B total premium, Part B IRMAA, Part D IRMAA, annual extra IRMAA, and the next income threshold.

The calculator does not add your actual Part D plan premium because that premium varies by plan. It shows only the Part D income-related adjustment that Medicare adds on top.

What Income Does Medicare Use for IRMAA?

For 2026, Social Security generally uses your 2024 modified adjusted gross income. In plain English, IRMAA MAGI is generally your federal adjusted gross income plus tax-exempt interest. That is why municipal-bond interest can matter even though it may be exempt from federal income tax.

If you are not sure whether a Roth conversion, IRA withdrawal, stock sale, Social Security benefit, municipal-bond interest, or another item belongs in your MAGI, use my IRMAA Income Checker first. The calculator is only as good as the MAGI number you feed it.

For the current published thresholds and premium amounts, see the CMS 2026 Medicare premium and IRMAA fact sheet. Social Security also publishes the 2026 Medicare premium tables and IRMAA guidance.

How to Use Planning / What-If Mode

This is the part I wanted the calculator to do differently from a basic bracket lookup. Sometimes your question is not “What is my IRMAA?” It is “What happens if I do something that changes my MAGI?”

Switch to Planning / What-If and start with the MAGI you expect before the potential transaction. Then add the items you want to test:

• Roth conversion: enter the taxable amount you expect to add to MAGI.
• Net capital gain: enter the taxable gain, not the gross amount you receive from selling the asset.
• QCD offset: enter a qualified charitable distribution only to the extent it replaces an IRA distribution that otherwise would have been included in the baseline MAGI.
• Other MAGI change: use this only for an increase or reduction you have independently verified.

The tool then compares the baseline with the what-if scenario and shows whether you cross a published IRMAA threshold.

That distinction matters. The older planning calculator effectively reused the 2026 table for future years. That can be useful for rough scenario work, but labeling the output as a future-year surcharge gives the number more certainty than it deserves. The rebuilt tool keeps the useful part — seeing whether a move changes your tier — while being explicit about what is and is not known.

If Roth conversions are the decision you are testing, my Roth conversion and IRMAA sizing guide goes deeper into the tradeoff between conversion tax, future RMDs, and Medicare surcharges.

How to Read Your IRMAA Calculator Results

The number that usually gets attention is the premium. The number I want you to notice is the threshold.

IRMAA works in income bands. Once MAGI moves into the next band, the corresponding monthly adjustment applies. That is why a transaction that barely crosses a threshold can have a much larger Medicare effect than the last few dollars of income would suggest.

• Part B total premium: the standard Part B premium plus any Part B IRMAA.
• Part B IRMAA: the income-related amount added to Part B.
• Part D IRMAA: the income-related amount added on top of your actual Part D plan premium.
• Annual extra IRMAA: the Part B and Part D income-related surcharges combined for 12 months, excluding your ordinary Part D plan premium.

For a full view of the published tiers, use my 2026 IRMAA brackets and Medicare surcharges guide.

What If Your Income Dropped? IRMAA and Form SSA-44

A calculator can correctly show a surcharge from the tax return SSA used and still not tell the whole story. If your income later fell because of a qualifying life-changing event, Social Security may allow you to request a new IRMAA determination using Form SSA-44.

Examples of qualifying events can include marriage, divorce or annulment, death of a spouse, work stoppage, work reduction, loss of income-producing property in qualifying circumstances, loss of pension income, and certain employer settlement payments. The facts matter, so do not treat “my income went down” as automatic appeal eligibility.

My IRMAA appeal and SSA-44 guide walks through that process separately. That keeps this page focused on the calculator job instead of turning it into a second appeal guide.

IRMAA Calculator FAQs

What is the 2026 IRMAA income threshold?

For 2026, IRMAA begins when 2024 MAGI is above $109,000 for individual filers or above $218,000 for married couples filing jointly. Married filing separately can use a different compressed table when you lived with your spouse during the tax year.

Does IRMAA use gross income or AGI?

Neither by itself. For Medicare IRMAA, MAGI is generally adjusted gross income plus tax-exempt interest. That is why the number can differ from the income figure you use casually when talking about spending or cash flow.

Does a Roth conversion count toward IRMAA?

The taxable amount of a Roth conversion generally increases AGI and therefore can increase IRMAA MAGI. The Medicare effect usually shows up two years after the income year, subject to the tax return SSA actually uses.

Can a capital gain trigger IRMAA?

Yes. A taxable net capital gain can increase AGI and push MAGI into a higher IRMAA band. Use the taxable gain, not the property’s sale price, when modeling the effect.

Does a QCD lower IRMAA?

A properly executed qualified charitable distribution can keep the qualifying IRA distribution out of gross income. In the calculator’s planning mode, the QCD field is therefore an offset to IRA income that otherwise would have been in your baseline MAGI — not a generic deduction from any income you want to remove.

Can I use this calculator for 2027 or 2028?

Use Planning / What-If mode to test how sensitive a hypothetical MAGI is to the published 2026 IRMAA thresholds. Do not treat those results as official 2027 or 2028 premiums. Those future thresholds and premium amounts change and should be updated when CMS and SSA publish them.

The Decision the Calculator Is Supposed to Help With

IRMAA is not a reason to automatically avoid income, a Roth conversion, a capital gain, or any other financial move. Sometimes paying more Medicare premium can still be part of the better long-term decision. The calculator’s job is narrower and more useful: show you when Medicare becomes another cost that belongs in the comparison.

If your what-if scenario crosses a threshold, that is your cue to compare the tax benefit, investment or estate-planning benefit, and Medicare cost together — not to let one surcharge make the decision by itself.