What is IRMAA? Medicare's income surcharge and the two-year lookback
The problem IRMAA creates
Most retirees notice IRMAA as a smaller January Social Security deposit. Medicare withholds the premium from the check. When income from two years ago crossed a line, the extra premium can show up before anyone connects it to a Roth conversion, IRA withdrawal, house sale, or last working year.
That timing gap is the whole problem: the financial move and the January surprise are two years apart.
What IRMAA is not
- Not a graduated tax. It is a cliff — $1 over the line costs the full tier surcharge for the year.
- Not based on this month's income. SSA uses a return already on file with the IRS.
- Not optional once you're on Medicare. If you have Part B and the line applies, the surcharge applies for that premium year.
- Not the same as the standard Part B increase. The "hold harmless" rule that protects some beneficiaries from standard premium hikes does not cover IRMAA. AARP explains the distinction.
The two-year lookback (why 2024 prices 2026)
SSA does not guess your current income. It uses the latest processed federal return. Official description: Medicare premiums for higher-income beneficiaries.
| Income year (MAGI on return) | Premium year affected | When people usually notice |
|---|---|---|
| 2024 | 2026 | January 2026 deposit shrinks |
| 2025 | 2027 | January 2027 |
| 2026 | 2028 | January 2028 |
Income you take this year is mostly about two Januarys from now — which is why couples compare Medicare cost before anyone touches the IRA.
2026 thresholds (from 2024 MAGI)
CMS published the 2026 Part B premium ($202.90) and income lines on November 14, 2025: 2026 Medicare Parts B premiums and deductibles.
| Tier | Single MAGI | Joint MAGI | Extra per person / year (approx.) |
|---|---|---|---|
| Base | ≤ $109,000 | ≤ $218,000 | $0 |
| Level 1 | $109,001+ | $218,001+ | $1,148.40 |
| Level 2 | $137,001+ | $274,001+ | $2,884.80 |
| Level 3 | $171,001+ | $342,001+ | $4,620.00 |
| Level 4 | $205,001+ | $410,001+ | $6,355.20 |
| Level 5 | $500,001+ | $750,001+ | $6,936.00 |
Married filing separately has a different published table. Qualifying surviving spouse, single, and head of household use the individual line ($109,000), not $218,000.
How to solve it (what you can actually do)
- See where you are. Filing status + MAGI from the lookback year → room before the line or dollars over. Two fields, no account.
- Align the household. Text the same card to a spouse (
#cliff=link) before a conversion or withdrawal. - Ask a CPA the right questions. Not "how much should I convert?" but "will this year's income shrink January's check two years later?"
- Check SSA-44 if you retired, lost a spouse, or had another listed life-changing event after the lookback year.
- Save the household if you will make several moves before the next November letter — $99/year keeps the lookback timeline on one board.
See whether this household crossed the line. Two questions. No account. Then a result you can text to your spouse.
Run the free checkHow Retirement Tax Radar fits
Generic IRMAA calculators answer "what tier am I in?" Retirement Tax Radar is built around the January check moment: two fields → a card that names room/over, the cliff cost in CMS dollars, and spouse share — then optional save for the multi-year lookback. It does not tell you how much to convert. It shows the Medicare cost of this household's income so you can decide with a CPA.
Related reading
Common questions
What does IRMAA stand for?
Income-Related Monthly Adjustment Amount — Medicare's official name for the income-based surcharge on Part B and Part D.
Does age change the income line?
No. The thresholds depend on filing status and MAGI. Age matters for whether you're on Medicare and whether one or two people pay the surcharge — not for where the line sits.
Can I appeal IRMAA?
If a life-changing event reduced income after the lookback year, SSA-44 may apply. SSA-44 guide · Official door: ssa.gov/medicare/lower-irmaa
Educational. Not tax, legal, or investment advice. Confirm the notice SSA actually mailed.