IRMAA Calculator: Your Medicare Surcharge from MAGI

This IRMAA calculator needs three facts from your 2024 tax return: filing status, adjusted gross income, and any tax-exempt interest. It adds them into the figure Social Security uses, finds your row in the 2026 tables, and returns your Part B premium, the drug plan add-on, the yearly cost for you or a couple, and the room left before the next row. The defaults describe a married couple with $214,000 of AGI and $6,000 of municipal bond interest.

IRMAA is short for the income-related monthly adjustment amount: an extra charge on Medicare premiums if your income exceeds certain thresholds. The Social Security Administration decides who owes it, and CMS sets the dollar amounts each fall. According to CMS, roughly 8% of Medicare beneficiaries on Part B pay it.

2026 IRMAA Brackets for Part B and Part D IRMAA

The standard monthly premium for Part B is $202.90 in 2026. Cross the first line and you pay more, in five steps (K = thousand):

MAGI, single	MAGI, joint	Monthly Part B total	Drug plan add-on
$109K or less	$218K or less	$202.90	$0
above $109K up to $137K	above $218K up to $274K	$284.10	$14.50
above $137K up to $171K	above $274K up to $342K	$405.80	$37.50
above $171K up to $205K	above $342K up to $410K	$527.50	$60.40
above $205K, under $500K	above $410K, under $750K	$649.20	$83.30
$500K or more	$750K or more	$689.90	$91.00

The single column also covers head of household and a qualifying surviving spouse. The drug add-on sits on top of your plan’s own Part D premium, so the actual premium you pay is plan price plus add-on. In the top bracket the total added per person is $578.00 a month, or $6,936 a year.

Married people filing separately who lived with their spouse at any point in the year get a harsher, three row table: $109K or less pays standard rates, anything above that and under $391K pays $649.20 for Part B plus $83.30 for drugs, and $391K or more pays $689.90 plus $91.00. Separate filers who lived apart the entire year are moved to the single table instead, a detail many tools skip. Our guide to IRMAA brackets walks through each row in more depth.

Estimate Your IRMAA: Three 2026 IRMAA Calculator Examples

Start with the default couple. Their AGI of $214,000 sits $4,000 under the joint threshold. Add back $6,000 of muni interest and MAGI becomes $220,000, the first surcharge row. Each spouse now pays a Part B IRMAA of $81.20 plus $14.50 on the drug side, $95.70 a month. That’s $1,148.40 per person per year and $2,296.80 for the two, all triggered by interest they never paid federal tax on.

A single filer at $150,000 lands one row higher: $405.80 for Part B plus $37.50, a $240.40 monthly IRMAA surcharge, or $2,884.80 a year.

The costly case: a married person filing separately with $120,000 who lived with a spouse pays $649.20 plus $83.30, or $529.60 extra a month. On a single return, the same income would cost $95.70.

Why Medicare Determines Your IRMAA From Income Two Years Prior

Medicare uses income from two years prior because that’s the most recent tax data the IRS can hand to SSA. The agency’s program manual (POMS HI 01101.010) says the lookback is generally two years and never more than three. So 2026 medicare premiums are based on your 2024 modified adjusted gross income, and 2027 will look at 2025.

The lag has a catch. You become eligible for Medicare at 65, but that first premium is set by income at 63, often a peak salary year or the year of a severance or stock sale. Someone who retired at 64 can be billed at a working income for a full year.

When the newest return isn’t on file, SSA may use the year before, then correct it once the newer data posts. Each year stands alone: the next IRMAA bracket arrives in a fresh notice, so the charge ends as soon as a later return comes in under the line.

What Counts Toward MAGI When IRMAA Is Calculated

IRMAA uses your MAGI, which here means adjusted gross income from line 11 of IRS Form 1040 plus tax-exempt interest income from line 2a. No deductions come off. The standard deduction and itemized deductions don’t help, because they’re subtracted after AGI.

Items that raise AGI and push a retiree up the table:

• Traditional IRA and 401(k) withdrawals, including a required minimum distribution.
• Roth conversions, taxed in full the year you convert.
• Capital gains from selling funds, a business, or a rental.
• Pensions, dividends, and other passive income.
• The taxable share of Social Security benefits.

Qualified Roth IRA withdrawals stay out of AGI, which makes tax-free Roth money a favorite tool for keeping the number low. An inherited IRA’s required withdrawals count too, and they’re easy to forget.

The 2026 IRMAA Surcharge and How You Pay It

Few people see a separate bill for the 2026 IRMAA surcharge. The surcharge added to both Medicare parts comes out of your monthly Social Security, Railroad Retirement Board, or OPM annuity check. If you don’t get one of those benefits, Medicare mails a bill, starting in December for the next year.

Choosing Medicare Advantage doesn’t avoid the higher premium. You still pay the standard Medicare Part B premium plus the adjustment, and the Part D surcharge applies to drug coverage from a stand-alone plan, an Advantage plan, or an employer. That add-on goes to Medicare, never the insurer, and CMS warns that skipping the bill can cost you that Medicare coverage for drugs. Your SSA notice lists the income used and the IRMAA amounts applied, and the premium amount comes out before your check arrives.

In short, the 2026 Medicare Part B charge is driven by the income table, not by plan choice. Original Medicare, a Medigap policy, and an Advantage plan all sit on the same base premium.

Life-Changing Events: How to Appeal Your IRMAA Determination

Income from two years back can be badly out of date. SSA will make a new decision from a more recent year if income dropped because of one of eight events:

1. Marriage.
2. Divorce or annulment.
3. Death of a spouse.
4. Work stoppage, which includes ordinary retirement.
5. Work reduction.
6. Loss of income-producing property from a disaster or other event outside your control.
7. Loss of employer pension income.
8. A settlement payment from an employer or former employer.

Form SSA-44 is how you report it, with proof of the event and either a newer return or an estimate of this year’s MAGI. If your income has dropped significantly since the lookback year because you retired, file it; for new retirees this is the main route to a lower bill. Start at SSA.gov/medicare/lower-irmaa or your local Social Security office. A one-time gain or a Roth conversion is not on the list, so plan those rather than hope to appeal them.

IRMAA Planning Before the Cliffs

The IRMAA thresholds have no phase-in. One dollar past a line charges the full step for the year, so a joint return at $218,001 costs a couple the same $2,296.80 as one at $274,000. When we review an income plan, we first check how close each year lands to a line; a few thousand dollars of conversion or harvested gains can cost more in Medicare surcharge than it saves in tax.

• Size Roth conversions to stop just under a bracket, then convert more next year.
• Spread large capital gains across two tax years.
• Give from an IRA directly to a charitable organization, which keeps that money out of AGI.
• Watch the year after a spouse dies. The survivor usually files single with half the threshold, which can mean a higher IRMAA on the same income.

For individuals in higher income brackets, the IRMAA impact is small next to the tax bill, but it’s predictable, and a medicare advisor or tax planner can map several years at once. Use our free calculator to estimate your Medicare costs: calculate your 2026 figures from the 2024 return, then rerun it each fall with projected income before deciding on conversions and sales by December 31. The IRMAA calculator’s room figure shows exactly how much income fits under the next line.

Frequently Asked Questions About 2026 Medicare IRMAA

At what income does it start?

For 2026, above $109,000 single or $218,000 joint. The surcharge is based on your income and filing status two years back.

How long do you pay IRMAA?

One year at a time. SSA recalculates yearly, and the charge stops once income falls under the line.

Do both spouses pay?

Each spouse enrolled in Medicare will pay an IRMAA based on the joint income, so a couple pays twice.

What do Medicare Part B and Part D premiums cost with no surcharge?

Part B is $202.90; Part D is whatever your plan charges. Part B and Part D costs rise only for returns over the line.

Where can I learn more about Medicare eligibility?

Medicare.gov covers enrollment, and CMS publishes premiums based on income each fall.

Calculator 2026 edition, last reviewed September 2026 against the CMS 2026 premium tables. CMS releases 2027 figures around November 2026. The calculator provides estimates only. This page is educational and is not tax, legal, or insurance advice.