Inherited IRA and Medicare IRMAA: How Distributions Can Spike Your Premiums

A $250,000 inherited IRA distribution taken in a single year can add $5,800 or more to your annual Medicare costs — two years later. Most beneficiaries never see it coming.

What is IRMAA?

IRMAA stands for Income-Related Monthly Adjustment Amount. It is a Medicare surcharge that increases your Part B and Part D premiums if your income exceeds certain thresholds. It is not a penalty — it is simply a higher premium tier. But for most people, it's a surprise: they think they know what their Medicare premiums will be, and then a large one-time income event (an inheritance distribution, a business sale, a Roth conversion) pushes them into a higher bracket, and they don't find out until Social Security sends a notice.¹

IRMAA is calculated separately for each Medicare beneficiary. For a married couple where both spouses are on Medicare, each spouse pays their own IRMAA surcharge based on the couple's combined MAGI (for joint filers). A single inherited IRA distribution can simultaneously raise both spouses' premiums.

The 2-year lookback

This is the detail that surprises most people. Your 2026 IRMAA surcharge is not based on your 2026 income. It is based on your 2024 MAGI — the most recent tax year for which the IRS has reported data to Social Security by the time your 2026 coverage begins.¹

The practical impact: if you take a large inherited IRA distribution in 2024, you will owe higher Medicare premiums in 2026. You will not feel the IRMAA cost until two years after the distribution. This makes it easy to overlook — and easy to trigger accidentally when planning a large distribution.

2026 IRMAA thresholds and Part B premium table

For 2026, the standard Medicare Part B premium is $202.90 per month. IRMAA surcharges apply when your 2024 MAGI exceeds the thresholds below. There are five income tiers; the first four are indexed for inflation annually (the fifth is frozen until 2028).¹²

Exact intermediate tier surcharge amounts vary. See the CMS 2026 Medicare fact sheet for the complete table. Part D surcharges ($14.50–$91.00/month) are additional. IRMAA per-person for each Medicare beneficiary; married couples each pay the surcharge.

How inherited IRA distributions count toward MAGI

Distributions from inherited traditional IRAs are ordinary income. They are reported on Form 1099-R and flow onto your Form 1040 as gross income. For IRMAA purposes, what matters is your MAGI — which, for most retirees, is very close to their adjusted gross income (AGI). MAGI adds back a few deductions (student loan interest, foreign income exclusion, IRA deductions) but for most Medicare-age taxpayers, MAGI ≈ AGI.

This means an inherited IRA distribution is, dollar for dollar, MAGI for IRMAA purposes. There is no special treatment, no exclusion, no averaging across years. If you withdraw $150,000 from an inherited IRA in 2024 and your other income is $80,000, your MAGI is $230,000 — which places you firmly in Tier 2 IRMAA and raises your 2026 Part B premiums by roughly $970+ per year, plus Part D surcharges.

The year-10 lump-sum trap

Under the SECURE Act 10-year rule, non-EDB beneficiaries must fully deplete their inherited IRA by December 31 of the 10th year after the original owner's death. A common — and costly — mistake: ignoring distributions during years 1–9 and then taking a single massive lump-sum distribution in year 10.

For inherited traditional IRAs, this is almost always the wrong strategy on tax grounds alone. But for Medicare-age beneficiaries, it can be catastrophic: a year-10 distribution of $500,000–$1M stacks entirely on top of other income, pushing MAGI several tiers into IRMAA territory and triggering the highest possible surcharges for the following two years.

Example: You inherit a $900,000 traditional IRA in 2025 from a parent who was 78 and already taking RMDs. You are 67 and on Medicare. Your normal income is $95,000 per year.

• If you defer all distributions and take a lump sum in year 10 (2035): At 7% average growth, the account reaches approximately $1.77M. That single distribution, added to $95,000 in regular income, produces MAGI of ~$1.86M — maximum IRMAA tier for 2037 and 2038. Your Medicare Part B alone adds $5,844/year, for two years. Plus Part D surcharges. Plus ordinary income tax at the top rate on the full $1.86M.
• If you spread distributions evenly over 10 years (~$180K/year at that growth rate): Each year your MAGI is approximately $275,000 — still in Tier 2–3 IRMAA, but never in the top tier. The IRMAA cost is real but not catastrophic, and more importantly, it's predictable and plannable.

The tradeoff is real: spreading distributions also triggers IRMAA across more years. But the math usually favors spreading — compressing $1.77M into a single year's MAGI is almost never optimal from a combined income tax + IRMAA standpoint.

Planning strategies for Medicare-age inherited IRA beneficiaries

1. Model the full 10-year MAGI trajectory before taking your first distribution

Before you touch the inherited IRA, project your MAGI for each year of the 10-year window. Include: Social Security income (85% is taxable if MAGI exceeds $34,000 single / $44,000 MFJ), pension income, dividends, capital gains, Roth conversions from your own IRA, and required inherited IRA distributions. Identify the years where you have "MAGI room" before you'd cross the next IRMAA tier — those are your best windows for larger inherited IRA distributions.

2. Front-load distributions in lower-income years

If you have years where your income will be lower — recently retired, before Social Security begins, before other income sources start — those years create room for larger inherited IRA distributions with less IRMAA exposure. The SECURE Act 10-year rule does not require equal annual distributions; you have complete flexibility in years 1–9 (subject to annual RMD requirements if the decedent was post-RBD at death — see the RMD rules guide).

3. Coordinate inherited IRA withdrawals with Roth conversions from your own IRA

Roth conversions also count as MAGI. If you are doing bracket-fill Roth conversions from your own IRA during the 10-year window (a common strategy), each Roth conversion competes with inherited IRA distributions for the same MAGI headroom before you cross an IRMAA tier. These two strategies need to be modeled together. See the Roth Conversion Coordinator for a tool that models both simultaneously.

4. QCDs for beneficiaries 70½ or older

If you are 70½ or older, you may be eligible for a Qualified Charitable Distribution (QCD) directly from your inherited traditional IRA to a qualified charity. For 2026, the QCD limit is $111,000 per year.³ A QCD satisfies part of your distribution obligation (it counts toward the 10-year depletion requirement) but is excluded from your MAGI entirely — it never appears on your Form 1040 as income. This is the most tax-efficient way to withdraw from an inherited traditional IRA for charitably inclined beneficiaries on Medicare. Each $111,000 QCD avoids both income tax and IRMAA on that amount.

Important: The 70½ age requirement is the beneficiary's age, not the original owner's age. You must be 70½ at the time of the distribution.

5. If you are under 65: plan before Medicare eligibility

If you inherited a large IRA at 52 and won't reach Medicare eligibility until 65, you have the most flexibility: IRMAA doesn't apply until you're enrolled in Medicare. This doesn't mean distributions carry no cost — income tax still applies — but coordinating distributions to fall before your Medicare start date removes the IRMAA dimension entirely. Distributions in your early-to-mid 50s, when other income may be lower, can be optimal from both an income tax and an IRMAA avoidance standpoint. Any large distributions taken in the year you turn 63 or 64 will appear in your MAGI at age 65 or 66, when IRMAA first applies.

6. Understand the "cliff" structure — $1 over the threshold costs hundreds

IRMAA brackets are cliff surcharges. If your MAGI is $108,999, you pay the standard $202.90 premium. If your MAGI is $109,001, you owe the surcharge on your entire premium — a jump of $81.20/month, or $974/year, from a single dollar of additional income. This cliff structure means that managing MAGI to stay just below a tier threshold can save nearly $1,000 per year. An inherited IRA distribution is a useful tool for this: it gives you a large, flexible income source you can calibrate year to year.

Does IRMAA affect both spouses?

Yes. IRMAA is assessed per Medicare beneficiary, based on the couple's joint MAGI for MFJ filers. If both spouses are on Medicare and the couple's combined MAGI exceeds the joint threshold, both spouses pay the surcharge independently. A married couple in Tier 2 ($218,001–$274,000 joint MAGI) each pays $284.10/month for Part B instead of $202.90 — doubling the IRMAA exposure. Inherited IRA planning for a married couple needs to account for both spouses' Medicare status and the combined income picture.

The IRMAA appeal: a narrow window that doesn't cover most inherited IRA situations

Social Security allows IRMAA appeals using Form SSA-44 when a "life-changing event" caused income in the lookback year to be higher than it will be going forward. Qualifying events include retirement, job loss, divorce, or death of a spouse — not a one-time inheritance distribution. If you receive a large inherited IRA distribution, it will likely not qualify for an IRMAA waiver through Form SSA-44.

This is precisely why planning distributions carefully before they happen matters more than appealing after the fact.

When to involve a specialist

The IRMAA problem is a multi-variable optimization across a 10-year window: federal income tax brackets, capital gains rates, Social Security taxation thresholds, IRMAA tiers, annual RMD requirements, and Roth conversion opportunities are all interacting simultaneously. Getting this right for a $300K–$2M inherited IRA is substantial planning work. Generalist advisors who default to equal 10-year distributions miss the IRMAA dimension. A specialist who models the full picture can often reduce total out-of-pocket costs (taxes + IRMAA surcharges) by tens of thousands of dollars over the window.

Sources

1. CMS — 2026 Medicare Parts A & B Premiums and Deductibles. Standard Part B premium: $202.90/month. IRMAA surcharge range: $81.20–$487.00/month additional. Single-filer threshold: $109,000. Joint-filer threshold: $218,000. Based on 2024 MAGI. Verified May 2026.
2. Kiplinger — Medicare Premiums 2026: IRMAA Brackets and Surcharges for Parts B and D. Full five-tier table for Part B and Part D IRMAA surcharges. Part D surcharges: $14.50–$91.00/month. Top combined Part B + D IRMAA exposure exceeds $7,000/year for highest earners.
3. IRS — QCD limit 2026: $111,000. Qualified Charitable Distributions excluded from MAGI. Annual limit per IRA owner (or beneficiary, if age 70½+). QCD counts toward the 10-year inherited IRA depletion requirement and toward any annual RMD obligation. Per SECURE 2.0 § 307, QCD limit is now indexed for inflation annually.
4. T.D. 10001 — Final RMD Regulations (July 2024). Annual RMD obligation in years 1–9 applies when the decedent died after their Required Beginning Date. The 10-year depletion rule is separate from the annual RMD requirement. Distributions above the annual minimum reduce the remaining 10-year balance.

IRMAA values verified as of May 2026 against CMS. Tax and Medicare rules are subject to change — verify current-year values at medicare.gov before making withdrawal decisions. This page covers 2026 Medicare thresholds based on 2024 MAGI.