Medicare · taxes
Once you enroll in Medicare, Part B and Part D premiums step up at modified-AGI cliffs. Cross a cliff by a dollar and you pay that tier for the whole year, per person. SSA usually opens the tax return from two years earlier. A 2026 bill looks at 2024 MAGI. A conversion or house sale you do in 2026 shows up on the 2028 premium. That lag is why people think the letter is a mistake. It usually is not.
Updated 2026-09-13 · 11 min read · Educational, not tax or Medicare advice. Run the IRMAA MAGI room calculator. Conversion extra-tax lives in the Roth conversion tool — this page does not rebuild it. Paid file: year-by-year MAGI map.
SSA POMS HI 01101.010: MAGI is Form 1040 line 11 (AGI) plus line 2a (tax-exempt interest). IRS sends the latest return it has — generally two years prior, not more than three. 2026 premiums → 2024 return. 2027 premiums → 2025 return. If you will enroll in Part B in 2028, this year’s MAGI is the one that prices it.
The CMS table on this page is the 2026 table (fact sheet dated November 14, 2025). Use it as a labeled stand-in when you model a 2026 conversion that will hit 2028 IRMAA. Those later floors will be higher. Do not freeze today’s $109,000 / $218,000 as 2028 law.
| Single MAGI (2024) | Joint MAGI (2024) | Part B total | Part D IRMAA | Extra / mo |
|---|---|---|---|---|
| ≤ $109,000 | ≤ $218,000 | $202.90 | $0 | $0 |
| > $109k–$137k | > $218k–$274k | $284.10 | $14.50 | $95.70 |
| > $137k–$171k | > $274k–$342k | $405.80 | $37.50 | $240.40 |
| > $171k–$205k | > $342k–$410k | $527.50 | $60.40 | $385.00 |
| > $205k–<$500k | > $410k–<$750k | $649.20 | $83.30 | $529.60 |
| ≥ $500,000 | ≥ $750,000 | $689.90 | $91.00 | $578.00 |
Source: CMS “2026 Medicare Parts A & B Premiums and Deductibles,” Nov 14, 2025; SSA POMS HI 01101.020. Part B total = $202.90 standard + IRMAA. Part D IRMAA sits on top of your plan premium. Extra / mo = Part B IRMAA + Part D IRMAA, per enrollee. Married filing separately who lived together: above $109,000 jumps to the $649.20 / $83.30 tier; ≥ $391,000 is the top.
Worked cliff
Single. MAGI pieces $50k wages + $28k taxable Social Security + $22k IRA = $100,000. Room under $109,000 = $9,000. Convert $10,000 more → MAGI $110,000. First 2026 surcharge: $81.20 + $14.50 = $95.70/mo × 12 = $1,148.40 for one enrollee. The last $1,000 of conversion bought a four-digit Medicare bill two years later.
The usual “no”
Work stoppage, marriage, divorce, death of a spouse, work reduction, loss of income-producing property, loss of pension, employer settlement — those are listed. A Roth conversion and a brokerage sale are not. File SSA-44 when you actually retired mid-year and the 2024 W-2 is still pricing 2026. Do not file it to unwind a conversion you already did.
Start with AGI. Wages, pension, taxable Social Security (up to 85%), traditional IRA and 401(k) withdrawals, Roth conversions, capital gains, rental, and Schedule C all sit there. Add municipal-bond interest. HSA and 401(k) deferrals still reduce AGI if you are eligible to make them. Roth withdrawals of contributed or converted basis (after the clocks) do not. A qualified charitable distribution from an IRA after age 70½ can satisfy an RMD and never hits MAGI — 2026 exclusion $111,000 per person (IRS Notice 2025-67). Trustee-to-charity. Not a donor-advised fund, not a 401(k).
That pairing is why QCDs show up in every serious RMD file: the table requires a withdrawal; the QCD keeps it out of the IRMAA stack. Sequence: RMD primer and RMD calculator. Do not take the RMD to checking in June and donate in December — MAGI already posted.
A $20,000 Roth conversion can be cheap federal tax in the 12% or 22% band and expensive Medicare two years later if it also trips a cliff. The extra-tax vs 12/22% room math lives in the Roth conversion calculator and the primer fill 12% or 22%. This page only owns the cliff: remaining MAGI room, the two-year lag, and whether a listed life-changing event can reprice the year. Do not dump the IRA into Roth in one December to “get it over with.”
Part A has no IRMAA. IRMAA is Part B and Part D. Each Medicare enrollee in the household pays their own surcharge — a couple both on Part B/D pays twice the monthly extra. Married filing separately while living together is the compressed table: one dollar over $109,000 is already the 80% tier.
Free tool
CMS 2026 table as a labeled two-year stand-in. Filing status, MAGI pieces, planned conversion, enrollees, shareable URL, bars.
PayPal
12-step calendar, SSA-44 evidence, QCD-before-RMD, MFS trap. Not a restatement of this table.
An extra Part B and Part D premium when MAGI from two years earlier sits above a statutory cliff. Cross by a dollar, pay the tier all year, per enrollee. Not an income-tax bracket.
Usually tax year minus two. 2026 premiums look at 2024 MAGI. A 2026 conversion is 2028 IRMAA. The 2026 CMS table is a stand-in for later floors.
AGI (line 11) plus tax-exempt interest (line 2a). Conversions, RMDs, and capital gains count. QCDs from an IRA after 70½ do not. Roth basis withdrawals do not.
No surcharge ≤ $109,000 single / ≤ $218,000 joint. Next single floors $137k, $171k, $205k, $500k. Joint is double until the $750k top. CMS Nov 14, 2025.
Part B IRMAA $81.20 + Part D $14.50 = $95.70/mo, $1,148.40/year per enrollee. Standard Part B without IRMAA is $202.90.
Two years later, if MAGI crosses a cliff. Run extra tax in the conversion calculator, then remaining room here. Do not rebuild conversions on this page.
Work stoppage is listed. File SSA-44 with the last paycheck. A conversion or stock sale is not listed. SSA will not undo a spike you chose.
Yes if you give anyway. 2026 cap $111,000 (Notice 2025-67), IRA only, trustee-to-charity, counts toward the RMD, stays out of AGI.
Educational only. Confirm the CMS fact sheet and SSA POMS HI 01101.010 / .020 for the premium year you care about. Written by Thomas Sanders.