Medicare IRMAA cliffs: why $1 over the line costs $1,148.40
Cliff vs bracket (the mental model)
| Federal income tax bracket | Medicare IRMAA | |
|---|---|---|
| Shape | Graduated — only dollars above the line taxed at the higher rate | Step — entire surcharge jumps at the line |
| $1 over the line | Costs a few cents to dollars in extra tax | Costs the full tier for twelve months |
| Timing | Same tax year | Usually two years later on the January check |
The first cliff in dollars (2026 premiums, 2024 MAGI)
Joint filers, both on Medicare, $217,999 MAGI → base premium. $218,001 MAGI → +$2,296.80 for the year (CMS Nov 14, 2025). The extra conversion, withdrawal, or bonus that pushed $2 over the line did not create a $2 surcharge — it triggered the whole tier.
That is why couples text each other a cliff card before touching the IRA: the decision is binary at the line, not proportional.
Every tier is a cliff
Level 1 → Level 2 is another full jump (about $1,736 more per person per year at 2026 CMS rates), not a smooth curve. Each tier has its own "room" before the next cliff. Retirement Tax Radar's card shows distance to the next line and dollar cost of crossing — not a recommended conversion amount.
What you should do with this information
- Know your room. Next line minus your MAGI = how much income headroom is left in the lookback year.
- Compare household impact. One spouse on Medicare vs both changes the total dollars, not the line.
- Separate Medicare cost from "should I convert?" Sometimes paying the surcharge is worth it. The card does not decide — it makes the Medicare line visible.
- Bring numbers to a CPA with the five questions on the printed card.
See whether this household crossed the line. Two questions. No account. Then a result you can text to your spouse.
Run the free checkRelated reading
Educational. Not tax, legal, or investment advice.