Grand Junction · Higher-income Medicare

What Is IRMAA for Married Filing Separately in 2026?

It is the steepest table Medicare has. A married person who files a separate return and lived with their spouse at any point in the year pays nothing extra up to $109,000 of income, and $529.60 a month extra for Part B and Part D from the next dollar. The three lower tiers that single and joint filers get do not exist. Here is the table, what it costs four different households, and the two ways out.

Medicare On Main Data Desk

Published September 30, 2026 · 9 min read · Reviewed by Brian Penner, 22+ years in Medicare

Yesterday's post on IRMAA and Medicare Advantage ended a table with one sentence: married people who file separately fall under a different, steeper table. A reader could fairly ask what that table is. It takes three rows to print and it surprises nearly everyone who lands in it, because the decision that put them there was made with a tax preparer, for tax reasons, two years before the Medicare bill showed up.

Mesa County had 41,709 people on Medicare in June 2026, according to the CMS monthly enrollment file. Most will never see a surcharge. For the married ones who file separately and have a pension, required distributions or a business still paying them, this is the rule that decides it.

The 2026 table for married people who file separately

CMS publishes it under a long heading: beneficiaries "who are married and lived with their spouses at any time during the year, but who file separate tax returns from their spouses." The amounts are per person, per month, on top of the standard $202.90 Part B premium and whatever your drug plan charges.

Source: CMS — 2026 Medicare Parts A & B Premiums and Deductibles / Part D Income-Related Monthly Adjustment Amounts. 2026 premiums are based on the 2024 return. Income here means modified adjusted gross income: adjusted gross income plus tax-exempt interest.

The same income on two different tables

The clearest way to see the difference is to take one person and change only the filing status.

Part B and Part D surcharges together, 2026 amounts, from the CMS fact sheet. The last row is where the two tables meet: a single filer reaches the same $529.60 once income passes $205,000.

Arithmetic on the amounts in the CMS 2026 fact sheet; amendment window from IRS Publication 501.

Why the table is built this way

IRMAA works by shrinking the government's share of your Part B premium. Most people pay about 25% of what Part B costs and the government pays the rest. The ordinary tiers raise the beneficiary's share to 35%, 50%, 65%, 80% and finally 85%.

The separate-filer table skips the first three steps. 20 CFR § 418.1120(b)(3) applies when "your Federal tax filing status is married filing separately, you lived with your spouse at some time during that tax year," and its table has two rows: 80% and 85%. Before inflation adjustments the range was "Greater than $85,000 but less than $415,000," and indexed to 2026 that is $109,000 to $391,000.

The reasoning is not hard to guess. A couple with $400,000 of joint income could otherwise split it across two returns and present Medicare with two people who each look like they sit in a lower tier. Social Security's own manual, POMS HI 01101.020, puts it in one line: "The law provides higher IRMAA levels for beneficiaries in this situation." The rule closes that door, and in doing so it catches couples who never had that in mind.

What it costs four households

Each row is a married couple, both on Medicare with drug coverage, priced at 2026 amounts. The joint column counts both spouses, because on a joint return both pay the same surcharge.

Our arithmetic on the 2026 individual, joint and separate-filer tables in the CMS fact sheet. Medicare surcharges only; income tax is not included and usually moves the other way.

The first two rows are the ones we see in Grand Junction. Two retired professionals with $110,000 each owe $2,296.80 a year on a joint return and $12,710.40 on separate ones. A couple where one spouse has the pension and the required distributions and the other has $40,000 owes nothing jointly, because $190,000 is under the $218,000 joint line. Filed separately, the higher-income spouse alone owes $6,355.20.

The last two rows are the exceptions. In the third row the couple is already in the fourth joint tier, so separate returns cost nothing more in surcharges; both tables charge $529.60 there. And when one spouse has nearly all the income, separate returns can take the other spouse out of the surcharge completely: $5,774.40 less in the last row. That is a real result, and it is not a recommendation. IRS Publication 501 says plainly, "You will generally pay more combined tax on separate returns than you would on a joint return," and the income tax difference at those incomes is usually larger than the Medicare one. It is a question for your tax advisor, with both numbers on the page.

If you lived apart all year

The steep table is for married people who lived together at some point in the tax year. The regulation puts the others somewhere else. Section 418.1120(b)(1) gives the general table to anyone whose status "is single; head of household; qualifying widow(er) with dependent child; or married filing separately and you lived apart from your spouse for the entire tax year." For a separated couple who have not divorced, that is the difference between $95.70 and $529.60 a month at $110,000 of income.

Social Security cannot see your living arrangements on the data the IRS sends. POMS HI 01120.060 says that when the filing status comes through as married filing separately, "SSA assumes the couple lived together at some point in the tax year." So the first notice will use the steep table, and it is on you to correct it. Three things to know:

• It is a sworn statement. "If one or both of the members allege living apart throughout the entire tax year, we will obtain an attestation to that effect under penalty of perjury." Entire year means what it says. A spouse who moved out in March does not qualify for that year.
• It is per person. "The change will be effective only for the individual who attests." If both spouses are on Medicare, both have to do it.
• There is a clock. The period to ask "begins with the date of the IRMAA determination notice until the end of the affected premium year." For a 2026 surcharge that is December 31, 2026. After that Social Security has to find good cause for the delay.

A spouse moving permanently into a care facility raises exactly this question, and the answer depends on the facts and the dates. Call Social Security at 1-800-772-1213 with the notice in hand.

Can the return be changed after the fact?

In one direction, yes. IRS Publication 501: "You can change your filing status from a separate return to a joint return by filing an amended return using Form 1040-X. You can generally change to a joint return any time within 3 years from the due date of the separate return or returns. This doesn't include any extensions."

Social Security has a matching rule. 20 CFR § 418.1150 says you may provide an amended return "within 3 calendar years following the close of the tax year for which you filed the amended tax return," with "a copy of the IRS letter confirming the amended tax return was filed or a transcript from IRS if they did not send a letter." Then: "We will then make any necessary retroactive corrections." For the second household above, that would mean the surcharge is corrected back to January of the year it was charged.

Both spouses have to agree to the joint return, and amending changes the income tax as well, in either direction. The other direction is closed: "Once you file a joint return, you can't choose to file separate returns for that year after the due date of the return."

Why couples file separately, and where Medicare fits

Nobody chooses this filing status for Medicare reasons. The ones we hear are a spouse on an income-driven student loan payment, one spouse with large medical bills measured against a smaller income, a business or a tax debt that one spouse wants kept on its own return, and second marriages where the finances were never combined. Those can all be sound reasons.

What is usually missing is the Medicare line in the comparison. Publication 501 tells couples to "figure your tax both ways (on a joint return and on separate returns)." Tax software does that for the tax. It does not add a surcharge that arrives two years later from a different agency. Once either spouse is 63 or older, the return being filed is one Medicare will read, and $6,355.20 per person belongs in the separate-returns column whenever that spouse's own income is over the line.

Which return counts, and what about 2027?

• 2026 premiums use the 2024 return. If it was filed separately, the IRS generally allows a change to joint until April 2028, and Social Security accepts the amended return through the end of 2027.
• 2027 premiums will use the 2025 return, already filed. The 2027 Medicare & You handbook prints the first threshold as "$111,000 if you file individually or $222,000 if you're married and file jointly." CMS had not published the 2027 separate-filer table or dollar amounts as of September 30, 2026; the 2026 ones came out on November 14, 2025.
• 2028 premiums will use the 2026 return, which has not been filed. The filing status for it gets chosen next spring, and that is the easiest one to get right.

Marriage and divorce are both on Social Security's list of life-changing events, which lets it use a more recent year. Choosing to file separately is not. The events and the form are in the SSA-44 appeal post; the federal rule is the same in Colorado.

What I would do

If you already file separately and one of you is on Medicare or within two years of it, ask your tax preparer one question before the 2026 return is filed: what does each status cost once the Medicare surcharge is included? Give them the table above. For most couples under $410,000 of combined income, that settles it in favor of the joint return.

If the notice has already come, read which filing status Social Security used. If you lived apart all year, tell them before December 31. If you lived together, take the notice to your tax advisor and ask whether amending to a joint return makes sense for that year. And keep paying the bill in the meantime. In Mesa County, 26.6% of adults live with high blood pressure and 8.1% with diabetes, per CDC PLACES, and an unpaid Part D surcharge can end drug coverage after a three-month grace period. A correction gets refunded. Lost coverage is harder to get back.

How we know all this: the Medicare On Main Data Desk frames every article with public data — here, the CMS fact sheet of November 14, 2025 for every 2026 Part B and Part D income-related amount, including the table for married beneficiaries who file separate returns; 20 CFR §§ 418.1115, 418.1120 and 418.1150, quoted as published on Cornell LII; the Social Security Administration's POMS sections HI 01101.020 and HI 01120.060; IRS Publication 501 for the filing-status rules; Medicare & You 2027 (page 86) for the 2027 first threshold; the CMS Medicare Monthly Enrollment file for Mesa County (June 2026); and CDC PLACES county data (2023). The household comparisons are our own arithmetic on the published 2026 tables, cover Medicare surcharges only, and are labeled as such. This is education, not advice; filing status is a tax decision for you and your tax advisor, and plans, costs and eligibility should be confirmed with a licensed agent or Medicare.gov. We take no payment from any carrier to feature a plan.